Traps

Traps can be found almost anywhere. One wrong step in an ancient tomb might trigger a series of scything blades, which cleave through armor and bone. The seemingly innocuous vines that hang over a cave entrance might grasp and choke anyone who pushes through them. A net hidden among the trees might drop on travelers who pass underneath. In a fantasy game, unwary adventurers can fall to their deaths, be burned alive, or fall under a fusillade of poisoned darts.

A trap can be either mechanical or magical in nature. Mechanical traps include pits, arrow traps, falling blocks, water-filled rooms, whirling blades, and anything else that depends on a mechanism to operate. Magic traps are either magical device traps or spell traps. Magical device traps initiate spell effects when activated. Spell traps are spells such as glyph of warding and symbol that function as traps.

Traps in Play

When adventurers come across a trap, you need to know how the trap is triggered and what it does, as well as the possibility for the characters to detect the trap and to disable or avoid it.

Triggering a Trap

Most traps are triggered when a creature goes somewhere or touches something that the trap’s creator wanted to protect. Common triggers include stepping on a pressure plate or a false section of floor, pulling a trip wire, turning a doorknob, and using the wrong key in a lock. Magic traps are often set to go off when a creature enters an area or touches an object. Some magic traps (such as the glyph of warding spell) have more complicated trigger conditions, including a password that prevents the trap from activating.

Detecting and Disabling a Trap

Usually, some element of a trap is visible to careful inspection. Characters might notice an uneven flagstone that conceals a pressure plate, spot the gleam of light off a trip wire, notice small holes in the walls from which jets of flame will erupt, or otherwise detect something that points to a trap’s presence.

A trap’s description specifies the checks and DCs needed to detect it, disable it, or both. A character actively looking for a trap can attempt a Wisdom (Perception) check against the trap’s DC. You can also compare the DC to detect the trap with each character’s passive Wisdom (Perception) score to determine whether anyone in the party notices the trap in passing. If the adventurers detect a trap before triggering it, they might be able to disarm it, either permanently or long enough to move past it. You might call for an Intelligence (Investigation) check for a character to deduce what needs to be done, followed by a Dexterity check using thieves’ tools to perform the necessary sabotage.

Any character can attempt an Intelligence (Arcana) check to detect or disarm a magic trap, in addition to any other checks noted in the trap’s description. The DCs are the same regardless of the check used. In addition, dispel magic has a chance of disabling most magic traps. A magic trap’s description provides the DC for the ability check made when you use dispel magic.

In most cases, a trap’s description is clear enough that you can adjudicate whether a character’s actions locate or foil the trap. As with many situations, you shouldn’t allow die rolling to override clever play and good planning. Use your common sense, drawing on the trap’s description to determine what happens. No trap’s design can anticipate every possible action that the characters might attempt.

You should allow a character to discover a trap without making an ability check if an action would clearly reveal the trap’s presence. For example, if a character lifts a rug that conceals a pressure plate, the character has found the trigger and no check is required.

Foiling traps can be a little more complicated. Consider a trapped treasure chest. If the chest is opened without first pulling on the two handles set in its sides, a mechanism inside fires a hail of poison needles toward anyone in front of it. After inspecting the chest and making a few checks, the characters are still unsure if it’s trapped. Rather than simply open the chest, they prop a shield in front of it and push the chest open at a distance with an iron rod. In this case, the trap still triggers, but the hail of needles fires harmlessly into the shield.

Traps are often designed with mechanisms that allow them to be disarmed or bypassed. Intelligent monsters that place traps in or around their lairs need ways to get past those traps without harming themselves. Such traps might have hidden levers that disable their triggers, or a secret door might conceal a passage that goes around the trap.

Trap Effects

The effects of traps can range from inconvenient to deadly, making use of elements such as arrows, spikes, blades, poison, toxic gas, blasts of fire, and deep pits. The deadliest traps combine multiple elements to kill, injure, contain, or drive off any creature unfortunate enough to trigger them. A trap’s description specifies what happens when it is triggered.

The attack bonus of a trap, the save DC to resist its effects, and the damage it deals can vary depending on the trap’s severity. Use the Trap Save DCs and Attack Bonuses table and the Damage Severity by Level table for suggestions based on three levels of trap severity.

A trap intended to be a setback is unlikely to kill or seriously harm characters of the indicated levels, whereas a dangerous trap is likely to seriously injure (and potentially kill) characters of the indicated levels. A deadly trap is likely to kill characters of the indicated levels.

Table: Trap Save DCs and Attack Bonuses

Trap Danger	Save DC	Attack Bonus
Setback	10–11	+3 to +5
Dangerous	12–15	+6 to +8
Deadly	16–20	+9 to +12

Table: Damage Severity by Level

Character Level	Setback	Dangerous	Deadly
1st–4th	1d10	2d10	4d10
5th–10th	2d10	4d10	10d10
11th–16th	4d10	10d10	18d10
17th–20th	10d10	18d10	24d10

Sample Traps

Traps vary in deadliness and are grouped by type (magic or mechanical) and then in alphabetical order. First listed are mechanical traps, then magical traps. Then, Hazards (like haunts), are listed next.

Traits

The line following the trap/hazard name is a list of traits that apply to that trait.

Magic

The trap has magical components.

Mechanical

The trap is mechanical in nature.

Mechanical and Magic Traps

Some traps have traits both mechanical and magical. They have both Magic and Mechanical traits and follow rules for both.

Simple Complexity

The simple trait…

Complex Complexity

Traps with the Complex trait work like those with the Simple trait, except once activated they execute a series of actions each round. A complex trap turns the process of dealing with a trap into something more like a combat encounter.

When a complex trap activates, it rolls initiative. The trap’s description includes an initiative bonus. On its turn, the trap activates again, often taking an action. It might make successive attacks against intruders, create an effect that changes over time, or otherwise produce a dynamic challenge. Otherwise, the complex trap can be detected and disabled or bypassed in the usual ways.

For example, a trap that causes a room to slowly flood works best as a complex trap. On the trap’s turn, the water level rises. After several rounds, the room is completely flooded.

Haunt

Haunts include supernatural or psychic-like components, or which are triggered by such. Haunts have unique defeat rules.

Trap

This trait separates a “trap” from a hazard like poison, disease, or otherwise passive environmental danger. Traps are intentionally designed to thwart, slow, delay, injure, kill, or more.

Mechanical Traps

The following traps do not include any magical or supernatural components. They are completely constructed of mundane, mechanical components.

Falling Net

Mechanical Trap

This trap uses a trip wire to release a net suspended from the ceiling.

The trip wire is 3 inches off the ground and stretches between two columns or trees. The net is hidden by cobwebs or foliage. The DC to spot the trip wire and net is 10. A successful DC 15 Dexterity check using thieves’ tools breaks the trip wire harmlessly. A character without thieves’ tools can attempt this check with disadvantage using any edged weapon or edged tool. On a failed check, the trap triggers.

When the trap is triggered, the net is released, covering a 10-foot-square area. Those in the area are trapped under the net and restrained, and those that fail a DC 10 Strength saving throw are also knocked prone. A creature can use its action to make a DC 10 Strength check, freeing itself or another creature within its reach on a success. The net has AC 10 and 20 hit points. Dealing 5 slashing damage to the net (AC 10) destroys a 5-foot-square section of it, freeing any creature trapped in that section.

Falling Stone Blocks

Source TM

Mechanical Trap

When a creature steps on a pressure plate with more than 20 lbs of force (or, in the case of weak construction, causes a large vibration by, for example, casting thunder wave), several stone blocks fall from the ceiling in a 10-foot radius around the creature. Each creature within the circle must make a DC 15 Dexterity saving throw. Those who fail the saving throw take 18 (4d8) bludgeoning damage while those who succeed take half this amount. The unstable state of the ceiling can be identified with a successful DC 14 Intelligence (Investigation) check.

Finding the pressure plate requires a DC 15 Wisdom (Perception) check.

The Drop and Plop CR 5-10

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. A pitfall trap that has a perfectly fitting gelatinous cube inside it. The pit is 10 feet by 10 feet and has a trap door at the top.

Trigger. One hundred pounds of pressure applied to the trap door (for instance, someone stepping on it), causes the trap door to open. Victims must make DC 14 Dexterity saving throw or fall in. The gelatinous cube immediately attacks anyone who falls in and automatically gains surprise.

Countermeasures. A DC 15 Wisdom (Perception) check reveals the presence of the trap door on the floor. Jumping over the trap door bypasses it, or a DC 14 Dexterity (Thieves Tools) check disables the trap door.

The Jelly Jamb CR 5-10

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. There is a glass pot of ooze above a door that triggers when the door is opened. The pot falls and shatters, releasing 1d4+1 ochre jellies that then attack the PCs!

Trigger. When the door is opened, the pot falls and breaks.

Countermeasures. The character that opens the door sees the pot falling. If they succeed on a DC 15 Dexterity saving throw, they can catch the pot if they want. The pot weighs 200 pounds and a character who catches it must make a DC 17 Strength (Athletics) check to not drop it and cause it to shatter.

Rusty Stuffings CR 1-4

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. In the corridor is a small, pink toy bear.

It’s actually a rust monster that has been polymorphed into a toy bear and is incapacitated while in that form.

The polymorph wears off five minutes after the toy bear has been placed into a container of any kind, such as a backpack. The rust monster then promptly begins to devour all metal items it can.

Countermeasures. Casting detect magic reveals a transmutation aura around the bear. The identify spell reveals the exact nature of the trap.

Golden Eye CR 5-10

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. A solid gold sphere sits in the middle of the room. When the sphere is touched, it opens, revealing a Death Kiss which promptly attacks.

Countermeasures. A successful DC 16 Wisdom (Perception) check reveals fine seams along the exterior of the sphere, indicating that it can be opened. Detect magic reveals an aura of abjuration about the sphere. A successful DC 13 Intelligence (Investigation) check reveals that the sphere is not made of gold, but iron painted over with gold.

Gold Dust Shroom Boom CR 1-4

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. Golden mushrooms are growing along the bottom of a chest, stretching about halfway up.

Below the mushrooms a large pile gold sparkles and beckons to the characters.

Trigger. Touching the mushrooms causes them to release a cloud of poisonous spores in a 10-foot radius. Everyone caught in the effect takes 2d6 poison damage or half as much if they succeed on a DC 12 Constitution saving throw. Once the spore cloud has been triggered, it takes 1d4 hours for the mushrooms to create more spores.

Countermeasures. A successful DC 13 Intelligence (Nature) check reveals that the poisonous nature of the mushrooms, including that it takes time to regenerate more spores once triggered.

The DoppelDoor CR 1-4

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Purpose. There is a magical doorway that teleports the first character to step through it into a pocket dimension (per the banishment spell) and replaces them with a doppelganger that looks exactly like them.

This effect lasts until the doppelganger dies, at which point the character is teleported to where the doppelganger perishes, taking the place of its body.

When this happens, the game master should take the player whose character was replaced away from the group, explain what has happened, and let them play the doppelganger. The GM should give the player some basic information to inform their roleplaying, such as the doppelganger’s motivations.

Countermeasures. A character who is suspicious of the doppelganger can make a Wisdom (Insight) check contested by the doppelganger’s Charisma (Deception) check. If the character wins, he notices small imperfections with the doppelganger’s disguise or acting, cluing him in that it is not actually the character.

The BrainWasher

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. In a room is a sink full of dirty dishes. A character who comes within 10 feet of the dishes feels magically compelled to clean them. They must succeed on a DC 15 Wisdom saving throw or be compelled to clean the dishes, a task that takes the next 15 minutes. If the character takes damage, they may repeat the saving throw, breaking out of the enchantment on a success.

At the end of 15 minutes, when the dishes have been cleaned, more dirty dishes magically fill the sink, and the character, and any others within range must make a new saving throw or be compelled to clean the dishes.

Countermeasures. Detect magic reveals an aura of enchantment magic around the dishes. Breaking all of the dishes causes the magic to fail, releasing anyone caught in its thrall.

Mimic Madness CR 5-10

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. A hallway contains three mimics that are concealing themselves as parts of the walls, floors, and doors. When the party is in the middle of the hallway, they attack.

Pleased to Meet You CR 5-10

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. A pair of large disembodied hands float in front of and block a passage. To get past, the characters must shake hands with them. If the hands are attacked or someone tries to push them out of the way, the hands slap the offenders. They have a +8 to hit and deal 4d10 bludgeoning damage.

Countermeasures. The characters notice an inscription on the wall near the hands that reads, “Foes don’t proceed; only friends shall we be.” This a clue that they need to shake the hands.

Fool’s Gold CR 5-10

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap (level 5-10, dangerous)

Description. A pot of gold coins sits on a table in a room. A character that removes gold from the pot must make a DC 15 Intelligence saving throw or suffer a hallucination that leprechauns are attacking them.

Countermeasures. Detect magic reveals an aura of enchantment magic around the pot. Placing the gold back into the pot releases the character from the hallucination. The hallucinations also wear off after 1d4+1 minutes.

The Baynard Curtain CR 1-4

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Purpose. Mark the characters so that they are easier for enemies to hit in combat.

Trigger. Vines over the mouth of the cave are tripwires that release buckets of phosphorescent powder.

Effect. Characters within 15 feet are covered in a phosphorescent powder that gives monsters using darkvision advantage on their Attack rolls against the characters for the next 1d4 hours if they fail a DC 14 Dexterity saving throw.

Countermeasures. The vine tripwires can be detected with a successful DC 13 Wisdom (Perception) check.

The tripwires can be disabled with a DC 12 Dexterity (Thieves Tools) check. Characters proficient in Nature have advantage on all interactions with the vines.

The powder can be removed from a character using a gallon of alcohol, such as ale, to clean it off.

GM Note. Combine this trap with guardians in the entrance of the cave that use darkvision. Thus, the trap makes the PCs more vulnerable to the guardians.

The Yeeter Totter CR 5-10

Source Trap Collection by TheDMLair. Author Luke Hart

Complex Mechanical Trap

Purpose. To throw PCs off the bridge and prevent them from passing.

Trigger. In the middle of the bridge on the railing is a small sign that reads “None Shall Pass.” These are magical letters, that when read causes the trap to spring.

Effect. When triggered, violent waves travel down the bridge for one round (6 seconds), causing the bridge to bounce up and down, similar to a trampoline. Players must succeed on a DC 15 Dexterity saving throw or be bounced off the edge of the bridge and be dangling from the side while grabbing the ropes. On the next round, dangling players must succeed on a DC 15 Strength saving throw or fall. Players who succeed on this saving throw are able to pull themselves back onto the bridge. Players who are not bucked off the bridge can help dangling players get back up, granting them advantage on their Strength saving throw.

Countermeasures. Detect magic will indicate that the entire bridge is covered in transmutation magic. Casting Dispel Magic will suppress the trap for 1d4+2 minutes. Casting Dispel Magic at level 5 or above, permanently dispels the trap.

Not Silent, Just Deadly CR 11-16

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Purpose. This is an ornate throne, designed to kill people.

Trigger. When someone sits on the throne, there is a squish as a sticky substance on the throne immediately bonds to the pants of the person sitting on the throne. Standing up from the throne pulls a pressure plate upwards, triggering the trap.

Effect. When triggered, a loud farting noise is emitted from the bottom of the throne as a large bladder full of poisonous gas is released into the room. Characters within 15 feet of the throne must make a DC 17 Constitution saving throw, taking 99 (18d10) poison damage on a failed save or half that damage on a successful save.

Countermeasures. Someone sitting on the throne can remove their pants to then get out of the throne without triggering it.

GM Note. Make there be an enticing reason that a character would want to sit in this throne. For instance, a sign reading “Don’t Sit Here” or “Free Gold” hanging above the throne might entice them to sit on it. Or you might make sitting on the throne seem necessary to advance in the dungeon, such as implying that it opens a secret door or something.

Scabaited CR 5-10

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

The sword itself is not magical. However, the scabbard emanates evocation magic when detect magic is used. Characters handling the scabbard can tell that it is magical, too. (This will probably make the character think the sword is magical.)

Purpose. Punish thieves who take the sword.

Trigger. Pulling the sword from the scabbard without first whispering the command phrase “Here I go killing again” triggers the trap.

Effect. Magical runes on the scabbard detonate, causing the scabbard to explode into a cloud of shrapnel, dealing 4d10 slashing damage to all creatures within 10 feet. Creatures who succeed on a DC 14 Dexterity saving throw take half damage.

Countermeasures. Casting detect magic reveals evocation magic on the scabbard. A successful DC 15 Intelligence (Arcana) check while studying the runes on the scabbard reveals that it explodes when the sword is drawn. Casting identify on the scabbard or sword (before drawn) reveals the command phrase.

The Bunny Blunder CR 1-4

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

There is a rope hanging from the ceiling with a golden carrot worth 50 gp tied to the end of it.

Purpose. To reward players with pain and suffering for being foolish enough to pull on a rope and carrot hanging from the ceiling.

Trigger. Pulling on the rope or removing the carrot from the rope.

Effect. A trap door opens on the ceiling, raining down 2d6 Killer Bunnies!

Countermeasures. A character searching the ceiling and succeeding on a DC 13 Wisdom (Perception) check notices that there is the outline of a trap door on the ceiling. Characters can bypass the trap by not pulling on the rope.

GM Note. Use the stat block for giant rat for the Killer Bunnies.

Octonote CR 5-10

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. A brass flute rests on a pedestal before a locked door. Playing any eight notes on the flute unlocks the door. Playing any other number of notes magically causes the hallway to fill with water and 1d4+2 giant octopuses that attack. Carved into the side of the pedestal are depictions of underwater scenes and aquatic creatures. Characters who succeed on a DC 14 Intelligence (Investigation) check while examining the pedestal discover that there are eight musical notes hidden among the carvings on the pedestal. Character proficient with a musical instrument gain advantage on the check.

Bark or Bite CR 1-4

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. There is a door with beautiful forest scenery carved into it, but it has no doorknob. Carved in the doorframe above the door in elven is “Be polite or I bite.”

Trigger. The door must be verbally asked to open in elven, and when someone does so, it swings open. However, anyone trying to open the door by physical means causes one swarm of insects (beetles) to burrow out from within the door and attack.

Bee-ware CR 1-4

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. This is a locked puzzle box always accompanied by a pot of honey that players might find among other loot. Every so often a BEEping sound emanates from a small hole on one side of the box. If characters look into the hole, they can see some treasure inside (see below). Touching the puzzle box leaves a sticky feeling on your hands. Smelling or tasting the substance reveals it is sweet like honey.

The game master should place level-appropriate loot in the puzzle box for players to be rewarded with.

Trigger. The puzzle box opens when honey from the pot is poured into a small hole on one side. When opened, a swarm of bees (use the stat block for swarm of insects (wasps)) emerges and attacks the character who has the pot of honey. If no one took the pot of honey, the wasps fly away.

Countermeasures. A character who inspects the box and the hole on its side spots the swarm of bees inside the box on a successful DC 12 Wisdom (Perception) check. Characters might use various methods to avoid being attacked by the bees. However, blowing smoke into the hole placates the bees, making them docile when the box is opened.

Double Vision CR 5-10

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. There is a mirror on the ceiling.

Trigger. When a character’s reflection is shown in the mirror by stepping below it, the character must make a DC 15 Charisma saving throw. On a failed save, the character is instantly teleported inside the mirror, and a doppelganger appearing exactly like the character takes their place. The character is trapped in the mirror in a sort of magical demi-plane until the doppelganger dies. Only one character at a time can be affected by this.

GM Note: When a character is swapped with the doppelganger, take the player aside and explain what happened in secret. Then have that player roleplay the doppelganger. That way the player isn’t just sitting out and doing nothing.

Countermeasure. Breaking the mirror nullifies the trap. If the mirror is broken while a PC is trapped within, they are released from within.

Over the Rainbow CR 1-4

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. There is a hallway with a floor painted with stripes of all the different colors of the rainbow.

Trigger. Walking on an incorrect stripe (any except red) at the midpoint of the hallway causes multicolored bolts of energy to shoot from the ceiling above at all characters in the hallway. The characters must make a DC 15 Constitution saving throw, taking 4d10 poison damage on a failed save, or half that much on a successful save.

GM Note: If desired, make the type of damage correspond to the color of the stripe the PC is walking on. Blue is electric, green poison, purple force, etc.

Countermeasures. Written in Draconic along the edge of the floor just before the hallway begins is “It’s Red or you’re Dead.” Characters succeeding on a DC 13 Wisdom (Perception) check notice this writing. If the characters only walk on the red stripe, the bolts of energy do not trigger.

e-MACE-iation CR 1-4

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. This appears to be a +1 mace when identified. However, it is a trap!

Trigger. Every time the mace is used in combat and successfully hits its target, roll a d12. On a 10, 11, or 12, the head of the mace explodes throwing shrapnel all about. Every creature in a 15-foot radius must make a DC 13 Dexterity saving throw, taking 2d6 piercing on a failed save, and half as much on a successful save. The wielder of the mace has disadvantage on the saving throw.

Countermeasures. A successful DC 12 Intelligence (Investigation) check reveals that the head of the mace is not stable and designed to break apart.

Piggy Bank

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. There is a hog on a spit roasting over a fire. The fire is illusory, as is the smell of beautiful bacon that fills the room. Characters interacting with the roasting hog recognize it for an illusion. The hog is actually a treasure chest filled with loot of the game master’s choice.

Trigger. When a character reaches through the hog’s mouth to extract the treasure, they must succeed on a DC 14 Wisdom saving throw or be polymorphed (per the spell) into a pig for 1d4 hours.

Countermeasures. A player who succeeds on a DC 14 Intelligence (Arcana) check notices magical runes carved into the flesh of the roasting hog, indicating the presence of some sort of polymorph effect. Casting dispel magic on the hog disables the trap for 1 hour.

Also, the loot can be successfully extracted from the piggy bank by reaching not through the mouth, but the other end. A successful DC 12 Wisdom (Perception) check reveals the presence of a small tag on one of the hog’s ears that reads, “Try the other end.”

Red Hots CR 5-10

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. A small jar contains 2d6 jellybeans.

Trigger. The beans are actually fireball pellets, albeit delicious ones. If a bean is eaten, a fireball immediately explodes in the consumer’s mouth. A fireball (per the spell, DC 16) goes off, centered on the person eating the bean. The person eating the bean automatically fails the saving throw. If the entire jar of beans is dumped out, all of them immediately detonate. (TPK baby! Lol)

Effect. The fireball jellybeans can be thrown up to thirty feet and explode per the fireball spell (save DC 16).

Countermeasures. Stop being dumb and eating weird food you find in dungeons!

Boots of Sticking and Snaring CR 11-16

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. There is a finely made pair of boots with magical aura cast on them, making them appear to be boots of striding and springing.

Trigger. There are small pressure plates in the heels of the boots. When someone puts the boots on and walks in them, the trap is triggered.

Effect. When triggered, sovereign glue oozes from the soles of the boots, on both the inside and the outside. It adheres fast to the PC’s foot and the floor, rooting them in place. The sovereign glue used in this trap sets in six seconds instead of one minute. (Once the glue has been used, it’s gone.) When triggered, the character feels something wet inside the boot and the boots seem to stick a little to the ground. If the character tries to remove the boots immediately, they must succeed on a DC 17 Strength saving throw in order to do so before the glue sets.

Countermeasures. A successful DC 15 Wisdom (Perception) check reveals that the soles of the boots are abnormally thick. Upon examining the thick soles, a successful DC 18 Intelligence (Investigation) check reveals the presence of a hidden compartment in the soles and how to open it. Inside the compartment on each boot is a bottle of sovereign glue for the taking, as long as the trap isn’t triggered first, which deploys the glue.

Mace-in-a-Box CR 1-4

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. A non-descript chest with no visible lock.

Trigger. Opening the lid triggers the trap.

Effect. When triggered, a spring-loaded mace inside the lid swipes in an arc at anyone standing in front of the chest. The mace has an attack bonus of +5 and on hit deals 4 (1d8) bludgeoning damage and the target must make a DC 14 Constitution saving throw. On a failed save, the target takes 7 (2d6) poison damage and is poisoned for one minute. On a successful save, the target takes half damage and is not poisoned.

Countermeasures. Opening the chest from the side or at range (such as with a ten-foot pole) bypasses the swinging mace. A successful DC 12 Wisdom (Perception) check reveals the presence of buckling wood on the backside of the lid as though something inside were pulling on the wood. A successful DC 13 Dexterity (Thieves’ Tools) check can disarm the trap.

Helm of the Catfolk CR 5-10

Source Trap Collection by TheDMLair. Author Luke Hart

Magic Trap Simple

Description. There is a finely made helmet shaped like the head of a jaguar with eyes of emerald on a pedestal worth roughly 200 gp.

Trigger. Removing the helmet from the pedestal trips a pressure plate which triggers the trap.

Effect. The character who moved the helmet is targeted by a polymorph spell. The character must make a DC 16 Wisdom saving throw. On a failed save, the character is polymorphed into a tiny cat for 1d4 hours. If as a cat the character is reduced to 0 hit points, they just turn into a different breed of cat. This can happen up to nine times, and on the tenth time of being reduced to 0 hit points, the character reverts to their normal self. Otherwise, this condition lasts until the spell ends or dispel magic is cast on the character.

Countermeasures. A successful DC 15 Wisdom (Perception) check reveals the presence of the pressure plate on the pedestal. The pressure plate can be neutralized, and the helmet removed if a character quickly swaps an item of equal weight with the helmet, placing that item on the pressure plate. The character must make a successful DC 15 Intelligence (Investigation) check to determine the weight of the helmet (twelve pounds). Then the character must make a successful DC 13 Dexterity (Sleight of Hand) check to swap the helmet with the item without tripping the pressure plate. If either of these checks fail, the trap is triggered.

Stairway to Slime CR 5-10

Source Trap Collection by TheDMLair. Author Luke Hart

Simple Mechanical Trap

Description. There is a ladder that must be climbed to get to the next level up.

Trigger. The sixth rung on the ladder pulls loose when climbed on and triggers the trap.

Effect. Triggering the trap causes a trap door in the floor to slide open, revealing a ten-foot-deep pit whose floor and walls are covered with green slime (see the game master’s core rulebook). The character who pulled the rung loose on the ladder must make a DC 14 Dexterity saving throw or fall into the pit. The character takes 1d6 falling damage and is covered with green slime, taking 5 (1d10 acid damage). The creature takes the damage again at the start of each of its turns until the slime is scraped off or destroyed. Against wood or metal, green slime deals 11 (2d10) acid damage each round, and any nonmagical wood or metal weapon or tool used to scrape off the slime is effectively destroyed.

Countermeasures. A successful DC 14 Wisdom (Perception) check reveals that one of the ladder rungs is loose.

Dart Trap CR 1—2

Simple Mechanical Trap

Appearance Several concealed holes adorn both sides of a room or corridor, with so many openings spread across that it’s impossible to pass without being in front of at least a few of them.

Trigger A creature or object weighing more than 20 pounds steps or lands on the pressure plate that activates the trap.

Detection A successful DC 15 Wisdom (Perception) check reveals the holes in the wall and the presence of a trap, but a separate DC 15 Intelligence (Investigation) check is required to reveal where the pressure plate is.

Disarming or Destroying A successful DC 15 Dexterity check using thieves’ tools disables the lever (if the person attempting it can reach the lever) or the pressure plate.

Damage and Effects When triggered, the Dart Trap fires 4 darts.

Each dart makes a ranged attack with a +8 bonus. These darts target a random creature within 10 feet of the pressure plate. Each creature that is hit takes 2 (1d4) piercing damage.

Some of these traps are poisoned (adding 1 to the CR), in which case any creature hit must succeed on a DC 15 Constitution saving throw, taking 11 (2d10) poison damage on a failed save, or half as much damage on a successful one.

Divide and Conquer CR 1

Simple Mechanical Trap

Appearance An empty room with a 6-inch deep and 12 inches wide trench dividing the room into two equal sizes, with two doors leading out of the room, diametrically across from each other.

Trigger A minimum of two creatures enter the room and are separated on each side of the room.

Detection A successful DC 11 Wisdom (Perception) check reveals the trap.

Disarming or Destroying A successful DC 11 Dexterity check using thieves’ tools disables it by jamming the wall mechanics. The trap cannot be destroyed, but the wall that slides down can. It has an AC of 17 and 50 hit points. The doors leading out on either side have an AC of 15 and 30 hit points, as they are steel-reinforced.

Damage and Effects When triggered, both doors close, and a wall slowly descends from the roof, separating the room into two. It does this slowly enough that anyone on one side can make it to another without issue.

On the wall is a lock. The lock unlocks the door on the other side of the room, and can be picked with a successful DC 12 Dexterity check using thieves’ tools. There is no other way of opening the doors on either side (i.e. to open the one on the left side, you must pick the lock on the right side, and vice versa). The doors can be opened from the outside of the room as normal, though they are locked. They can still be picked as normal.

The trap resets when the doors are opened at the same time.

GM’s Note: This trap is deliberately designed to slow down or restrain the heroes from going anywhere. Not all trap-makers want to kill people.

Elevator Room CR 1

Simple Mechanical Trap

Appearance An empty room with 4 doors, one on each wall.

Trigger A minimum of one creature enters the room and spends 1 round in the room.

Detection A successful DC 12 Wisdom (Perception) check reveals the trap.

Disarming or Destroying A successful DC 12 Dexterity check using thieves’ tools disables it by jamming the elevator mechanics. The doors can be destroyed. Each has an AC of 17 and 20 hit points. They can also be forced open with a DC 20 Strength (Athletics) check.

Damage and Effects When triggered, any open doors close 1round later, to trap as many people as possible.

Once the doors close, they lock and the room descends, one level (or 20 feet) per round. This continues until the Elevator Room reaches the bottom at which time the doors open.

GM’s Note: This trap is deliberately designed to bring creatures in over their heads and is only used in dungeons and other areas where there is a significant increase in danger the further one goes. As such, it is not unusual to find these in the lairs of liches and dragons, who often find that those caught in such a simple trap make for easy fodder.

Falling Net CR 1

Simple Mechanical Trap

Appearance A net is suspended from above, with a tripwire activating the trap, capturing those caught beneath it.

Trigger When a creature moves the tripwire the trap triggers.

Detection A successful DC 10 Wisdom (Perception) reveals the tripwire and the net.

Disarming or Destroying A successful DC 15 Dexterity check using thieves’ tools breaks the tripwire harmlessly.

Anyone with an edged weapon or tool can attempt the check, but they have disadvantage when doing so. Failing the check triggers the trap.

Damage and Effects When the trap is triggered, the net releases, covering a 10-foot-by-10-foot area.

Those within that area are restrained and those that fail a DC 10 Strength saving throw are knocked prone.

A creature can free itself (or any creature in range) by using an action to make a DC 10 Strength (Athletics) check and succeeding.

The net has AC 10 and 20 hit points, and for each 5 slashing damage dealt, a 5-foot square section is destroyed, which frees any creatures trapped in that section.

GM’s Note: An alternate version of this has the net spread on the ground, and when triggered, pulls the creatures in the area into the air, suspending them from above, at least 20 feet up. This works similarly to the falling net, but any creatures who free themselves (or where the net is destroyed) fall to the ground taking 7 (2d6) bludgeoning damage (this increases the CR of the trap to 2).

Falling Wasp Nest CR 1

Simple Mechanical Trap

Appearance A small wire or string is stretched across the ground, set to trip anyone crossing it. Once tripped, a wasp nest falls from a perch above, pulled down by the string, breaking it open and unleashing the angry wasps.

Trigger A creature triggers the wire.

Detection A successful DC 12 Wisdom (Perception) check reveals the trap.

Disarming or Destroying A successful DC 10 Dexterity check using thieves’ tools disables it. The trap can be destroyed by dealing 1 point of damage to it. It has an AC of 12.

Damage and Effects The trap drops a wasp nest from at least 10 feet above, breaking it open upon impact with the ground. The wasps immediately stream out and sting anyone within a 10 foot radius.

Anyone within a 10 foot radius must make a DC 10 Dexterity saving throw. On a failed save, a creature takes 3 (1d6) piercing damage, or half as much on a successful one. The wasps remain in the area for 1 minute, attacking anyone who comes into the radius. After 1 minute they disperse automatically.

Ladder To Nowhere CR 1

Simple Mechanical Trap

Appearance A square trapdoor with 2-½-foot long sides in a scuffed wooden floor reveals a metal ladder that descends to an unlit room below. The ladder is bolted to the wall of the room below.

Trigger A lever disguised to look like a ladder rung is located 50 feet down the 70-foot long ladder.

When five pounds of pressure is applied to the rung, it triggers a mechanism hidden behind the wall that releases a block of stone concealed in the ceiling in the room above.

Detection If a creature examines the ceiling, a successful DC 15 Wisdom (Perception) check reveals the seams of a square outline with 3-foot long sides. If a creature examines the ladder as they descend it, a successful DC 15 Wisdom (Perception) check reveals the false ladder rung.

Disarming or Destroying A successful DC 5 Dexterity check allows a creature to avoid the ladder rung that triggers the trap. A successful DC 10 Dexterity check using thieves’ tools disarms the trap as the hero stabilizes the false rung.

Damage and Effects When the lever activates, a 3-foot long by 3-foot wide by 6 inches thick cut-out section of the stone ceiling in the top room is released and lands over the trapdoor sealing off the room’s only exit. The stone slab weighs 800 pounds, which can be pushed, dragged, or lifted as normal.

Pit Trap CR 1—5

Simple Mechanical Trap

GM’s Note: Pit Traps are generally put into three categories: Standard (CR 1), Hidden (CR 2), and Locking (CR 3). Any of these can have spikes and other nasty effects added to them (Adding 1 to the CR). Finally, a spiked pit can have an injury poison on the spikes (which adds a further 1 to the CR for a total of 2 for spikes and poison).

Appearance A hole in the ground hidden beneath a carpet, blanket, or similar material that hides the opening. The hole drops down at least 10 feet.

Trigger A creature steps on the covering material.

Detection Standard: A successful DC 10 Wisdom (Perception) check reveals the trap.

Hidden: A successful DC 15 Wisdom (Perception) check reveals the trap as the hero discerns the lack of traffic across that section of ground. For the hidden pit, it is always a trapdoor that covers the hole, making it blend almost seamlessly with the ground.

Locking: A locking pit is similar to a hidden pit for detection purposes.

Disarming or Destroying Standard: A standard pit trap cannot be disarmed, and destroying it is a simple matter of filling the hole with dirt or some other material.

Hidden: The trapdoor of a hidden pit can be disabled with a DC 11 Dexterity check using thieves’ tools to jam the trapdoor, preventing it from opening. The trapdoor can also be destroyed. The AC and hit points depend on its material, but in most dungeons, it is made of stone and has an AC of 17 and 20 hit points.

Locking: The trapdoor of a locking pit functions like the trapdoor of a hidden pit, but opening the lock requires a DC 15 Dexterity check using thieves’ tools if the trap has already been triggered (before this point, it can be disabled like a hidden pit). It has the same AC and hit points as a hidden pit, but the trapdoor can be pried open with a successful DC 20 Strength (Athletics) check.

Damage and Effects All pits deal damage to those who fall into them, depending on the depth. For every 10 feet deep that the pit is, it deals 3 (1d6) bludgeoning damage (Up to a maximum of 20d6). Most pits are between 10 and 20 feet deep.

Spiked pits have sharpened stakes at the bottom of the pit, often made from wooden stakes or iron spikes. These deal an additional 11 (2d10) piercing damage on top of the falling damage.

Finally, some of the spiked traps have poison smeared on them. This can be any poison of the creator’s choice, but the most typical one requires a DC 13 Constitution saving throw, taking 22 (4d10) poison damage on a failed save, or half as much damage on a successful one.

Ankle Chopper CR 2

Simple Mechanical Trap

Appearance A set of wooden stairs leads up to an open door.

Trigger When stepped on, the tread halfway up the staircase is a pressure plate that pulls the panel on the step’s riser down.

Detection If a creature examines the step, a successful DC 10 Wisdom (Perception) check reveals a different sound behind the trapped riser.

Disarming or Destroying A successful DC 5 Dexterity check allows a creature to skip the trapped step to avoid triggering the trap. A DC 10 Dexterity check using thieves’ tools will successfully support the pressure plate to keep it from depressing and prevent the trap from tripping.

Damage and Effects A handaxe springs out from under the stair and strikes the shin of the creature that stepped on the pressure plate dealing 1d6 + 1 point of slashing damage. Simultaneously, grease is released that flows down the stairs.

Each creature on the staircase must make a successful DC 11 Dexterity save or slip and tumble down to the base of the stairs taking the appropriate amount of damage for the distance fallen.

Bear Trap CR 2

Simple Mechanical Trap

Appearance A set of iron jaws, in the form of a bear trap, are set upon the ground and covered.

Trigger A creature steps on the bear trap.

Detection A successful DC 10 Wisdom (Perception) check reveals the trap.

Disarming or Destroying A successful DC 10 Dexterity check using thieves’ tools disables it. The trap can be destroyed by dealing 5 points of damage to it. It has an AC of 12.

Damage and Effects The trap makes an attack against the triggering creature. The attack has a +8 attack bonus and deals 5 (1d10) piercing damage on a hit. This attack can’t gain advantage or disadvantage. A creature hit by the trap has its speed reduced to 0. It can’t move until it breaks free of the trap, which requires a successful DC 15 Strength check by the creature or another creature adjacent to the trap.

Crushing Door CR 2

Simple Mechanical Trap

Appearance A closed wooden door.

Trigger Turning the door handle.

Detection A successful DC 10 Wisdom (Perception) check reveals deteriorated hinges and no airflow coming from under the crack of the door.

GM’s Note: There’s no airflow because it’s a false door. There is no room behind the door, only a wall.

Disarming or Destroying A successful DC 10 Dexterity check using thieves’ tools jambs the mechanism in the handle so it can’t release acid onto the hinges.

Damage and Effects Acid coats the hinges causing them to dissolve which releases the door that falls forward onto the creature that triggered the trap. The creature must make a DC 10 Dexterity saving throw. On a failed save, the creature takes 11 (2d10) bludgeoning damage and is pinned under the door, or half as much damage on a successful save. A creature is not pinned on a successful save. Every round a creature starts its turn pinned under the door, it takes 1d6 points of bludgeoning damage. A creature can use its action to push the door off a pinned creature with a successful DC 15 Strength (Athletics) check.

Seat of Entrapment CR 2

Simple Mechanical Trap

Appearance An ornate, stone throne sized for an adult humanoid with a coin-sized ruby embedded on each of its arms.

Trigger Sitting on the throne with at least 50 pounds of weight releases a concealed catch underneath the seat that is holding the stone arms in place.

Detection A successful DC 10 Wisdom (Perception) or Intelligence (Investigation) reveals the concealed catch under the seat and the sliver of a groove where the hinges are located at the spots where the arms and the back of the chair meet.

Disarming or Destroying A successful DC 10 Dexterity check using thieves’ tools to block the catch from releasing will prevent the trap from tripping. If the trap is tripped, a creature that is not pinned in the throne can make a successful DC 12 Strength (Athletics) check to manually reset the catch under the seat which will release the arms and reset them to their original open position.

A creature pinned in the chair can make a successful DC 12 Dexterity (Acrobatics) check to wriggle free from the arms. A creature larger than Medium makes the check at disadvantage.

Damage and Effects When the trap triggers, a creature sitting on the throne can make a DC 12 Dexterity saving throw to leave the throne before the released arms come together to entrap the creature on the throne. A creature sitting on the throne when the arms come together takes 11 (2d10) points of bludgeoning damage and gains the restrained condition.

Corpse Box CR 3

Simple Mechanical combination trap

Appearance An ornate stone coffin decorated with images of people being trapped alive inside it.

Trigger A creature opens the trap.

Detection A successful DC 14 Wisdom (Perception) check reveals the trap. Detect magic reveals an aura of conjuration magic emanating from inside the coffin.

Disarming or Destroying The Corpse Box cannot be disabled through mechanical means, though it can be opened after it has triggered with a successful DC 14 Dexterity check using thieves’ tools. The trap can be destroyed by dealing 15 points of damage to it. It has an AC of 16. This destroys the lid, and if there is a trapped occupant, they can escape.

Damage and Effects As tentacles emerge, the trap makes an attack against the triggering creature. The attack has a +5 attack bonus and deals 5 (1d10) bludgeoning damage and the target is grappled (escape DC 17). Until this grapple ends, the creature is restrained.

The target is then dragged into the coffin which slams shut revealing that it is lined with spikes, which pierce the trapped occupant.

This automatically causes 10 (2d10) piercing damage on each round that the creature is trapped.

Once the occupant is dead, the trap opens and the corpse is expelled. This resets the trap.

Deterring Door CR 3

Simple Magic Mechanical Trap

Appearance An immobile door with no obvious knob or lock has an intricate brass knocker on it in the form of a jester’s head.

Trigger A creature that uses the knocker triggers the trap.

Detection A successful DC 15 Wisdom (Perception) check or DC 15 Intelligence (Arcana) check reveals an arcane symbol on the underside of the door knocker incorporated into its elaborate design. Detect magic reveals abjuration and enchantment auras on the door.

Disarming or Destroying Dispel magic (DC 12) will dispel the enchantment magic and the arcane lock on the door.

Damage and Effects The arcane lock spell doesn’t deal damage to nearby creatures, but it does keep them from entering unless they employ a knock spell or physically destroy the door.

After a creature uses the door knocker, they hear the following words (in Common) in their mind: “Travel as far away from here as you possibly can.” If the creature doesn’t understand common or can’t be charmed, it is immune to the effects. Otherwise, it must make a DC 12 Wisdom saving throw. On a failed save, the creature must comply with the request to the best of its ability for the next hour.

Hall of Mirrors CR 3

Simple Magic Mechanical Trap

Appearance A hallway (25-feet long & 5-feet wide) with an arch at both ends has several paintings, ornate mirrors, and clay busts lining the walls. A thin red carpet runs down the center of the hall. A carved lion’s head adorns the top of the first arch. When a creature approaches within 5-feet of the lion’s head, a magic mouth spell activates and the lion says, “speak the password or go no further”.

Trigger A creature passes under the exit arch without having said “the password” aloud.

Detection Detect magic on the second arch reveals an aura of evocation magic. A successful DC 15 Intelligence (Investigation) or Intelligence (Arcana) check reveals a glyph inscribed on the underside of the exit arch.

Disarming or Destroying Dispel magic (DC 12) dispels the glyph. A successful DC 15 Intelligence (Arcana) ability check also destroys the glyph as the hero disrupts the magic pattern of the glyph.

Detect magic reveals an aura of illusion magic centered on the sigil.

Damage and Effects As the glyph triggers, it releases a shatter spell.

All creatures within 10 feet of the exit arch must make a DC 12 Constitution saving throw.

A creature takes 13 (3d8) thunder damage on a failed save, or half as much on a successful save. Simultaneously, the mirrors shatter and send flying glass shards into the hallway.

All creatures within 10 feet of the exit arch must make a DC 15 Dexterity saving throw. A creature takes 13 (3d8) slashing and piercing damage on a failed save, or half as much on a successful save.

Lure of Greed CR 3

Simple Mechanical Trap

Appearance A backpack, sack, or chest that has been badly hidden.

Trigger A creature opens or moves the container.

Detection A successful DC 13 Wisdom (Perception) check reveals the trap.

Disarming or Destroying A successful DC 15 Dexterity check disables it. Failing the check triggers the trap. The trap cannot be destroyed without destroying the container.

Damage and Effects The trap unleashes a cloud of poison in a cone 10 feet long, centered on the container, in the direction of the creature opening it. All creatures within the cone must make a DC 12 Constitution saving throw. On a failed save, it takes 6 (1d12) poison damage and is poisoned for 24 hours. On a successful save, the creature takes half damage and isn’t poisoned.

The container may or may not be full at the GM’s discretion, but it is likely empty as it was badly hidden on purpose to tempt would-be thieves into disturbing it.

Needle Trap CR 3

Simple Mechanical Trap

Appearance A chest or door, or similar object that a creature would want to open.

Trigger The object is opened, triggering the trap.

Detection A successful DC 20 Intelligence (Investigation) check reveals the presence of the trap, as alterations are made to the locking mechanism of the object. Casual inspection, such as with a Wisdom (Perception) check, is not enough to reveal the presence of the trap.

Disarming or Destroying A successful DC 15 Dexterity check using thieves’ tools disarms the trap, allowing the object to be opened safely. Failure triggers the trap.

Damage and Effects When the trap is triggered a needle extends 3 inches straight out from the lock, damaging the creature manipulating the object. That creature takes 1 piercing damage and 11 (2d10) poison damage and must succeed on a DC 15 Constitution saving throw or be poisoned for 1 hour.

Punji Sticks CR 3

Simple Mechanical Trap

Appearance Several sharpened sticks, usually smeared with sewage or other diseased filth, strike from tension, impaling a victim.

Trigger When a creature moves the tripwire the trap triggers.

Detection A successful DC 15 Wisdom (Perception) check reveals the tripwire.

Disarming or Destroying A successful DC 15 Dexterity check using thieves’ tools cuts or disables the trip wire safely (the person making the check can reset the trap if they wish). Anyone with an edged weapon or tool can attempt the check, but they have disadvantage when doing so. Failing the check triggers the trap.

Damage and Effects When triggered, the punji sticks strike out, attacking the triggering creature. The sticks make a single melee attack with a +8 bonus.

The triggering creature takes 6 (3d4) piercing damage if they are hit.

They must also make a DC 10 Constitution saving throw or contract a nasty disease. If they fail the saving throw, they become poisoned until the disease is cured. For every 24 hours that elapse, the target must repeat the saving throw, reducing its hit point maximum by 2 (1d4) on a failure. The disease is cured on a success. The target dies if the disease reduces its hit point maximum to 0. This reduction to the target’s hit point maximum lasts until the disease is cured.

This trap must be manually reset.

Rope Bridge Trap CR 3

Simple Mechanical Trap

Appearance A rickety bridge crosses a large chasm.

Trigger When more than two Medium-sized creatures step on the bridge, it collapses, or it is activated by a creature cutting one of the ropes.

Detection A successful DC 12 Wisdom (Perception) reveals that the bridge is unstable and could collapse if too much weight is put on it.

Disarming or Destroying The trap cannot be disarmed. Destroying it is a simple matter of cutting the ropes, which have an AC of 5 and 2 hit points. This drops any creatures currently on the bridge into the chasm below.

Damage and Effects When activated, the triggering creatures are dropped to the chasm below unless they succeed on a DC 17 Dexterity saving throw.

Each creature takes falling damage from the drop (typically this drop is at least 50 feet, meaning they take 17 (5d6) bludgeoning damage). Some trapmakers fill the chasm below with spikes like a pit trap. These deal an additional 11 (2d10) piercing damage on top of the falling damage. (and increases the CR by 1) Finally, some of the spikes may have poison smeared on them. This can be any poison of the creator’s choice, but the most typical one requires a DC 13 Constitution saving throw, taking 22 (4d10) poison damage on a failed save, or half as much damage on a successful one. (which increases the CR by a further 2, to a total of 6).

Sewer Pit CR 3—4

Simple Mechanical Trap

Appearance A trap door drops the heroes into a pit. The door then closes and the pit trap fills with sewage.

Trigger A creature steps on the trap door.

Detection A successful DC 12 Wisdom (Perception) check reveals the trap.

Disarming or Destroying A successful DC 12 Dexterity check using thieves’ tools disables it by jamming the trap door closed. The trap door can be destroyed (AC 14 and 15 hit points), but this only leaves the pit open and creatures can still fall into it.

Damage and Effects Any creature that falls into the 30-foot deep pit takes 3d6 bludgeoning damage from the fall.

Immediately thereafter the cover closes, and the pit begins to fill with a mix of sewage and water.

After 2 rounds the pit is filled, and the creature must hold its breath or begin drowning.

They must also make a DC 10 Constitution saving throw or contract a nasty disease. If they fail the saving throw, they become poisoned until the disease is cured. Every 24 hours that elapse, the target must repeat the saving throw, reducing its hit point maximum by 2 (1d4) on a failure. The disease is cured on a success. The target dies if the disease reduces its hit point maximum to 0. This reduction to the target’s hit point maximum lasts until the disease is cured.

A successful DC 20 Strength (Athletics) check is necessary to pry the cover open. The cover can also be smashed open. A character in the pit can also attempt to disable the spring mechanism from the inside with a DC 15 Dexterity check using thieves’ tools, provided that the mechanism can be reached and the character can see. In some cases, a mechanism (usually hidden behind a secret door nearby) opens the pit.

GM’s Note: Some of these only fill with normal water, drowning the triggering creature. These are CR 3.

Smoke & Arrows CR 3

Simple Mechanical Trap

Appearance A 15-feet-by-15-feet torch-lit foyer has two wooden statues armed with light crossbows.

The statues stand on opposite walls 5 feet into the room.

Trigger A trip wire stretched between the two statues causes the crossbows to fire.

Additionally, a pressure plate is located directly in front of the exit door at the other end of the foyer.

Detection A DC 5 Wisdom (Perception) check reveals that the crossbows are functioning.

GM’s Note: This is the “red herring”. The heroes are supposed to discover this part of the trap, to lure them into missing the second one.

A successful DC 8 Wisdom (Perception) check reveals the trip wire.

A successful DC 15 Wisdom (Perception) check reveals all of the following: the pressure plate, the secret compartment on the wall behind the lit torch at the exit door, and a scorch mark on the wall near the torch.

Disarming or Destroying A successful DC 13 Dexterity check using thieves’ tools allows a creature to snip the trip wire without triggering the first part of the trap.

The crossbows can be removed and used as functioning weapons.

A successful DC 13 Dexterity check using thieves’ tools will prevent either the pressure plate or the secret compartment from functioning as the hero jams them in place.

Damage and Effects One crossbow bolt from each statue attacks the creature activating the trip wire. Each bolt makes a ranged attack with a +8 bonus, and deals 1d8 piercing damage.

As the pressure plate depresses, a secret compartment on the wall behind the lit torch slides open, and oil is sprayed onto the torches causing a burst of fire to flare up in a 5-foot radius. Creatures in the radius must make a DC 12 Dexterity saving throw. On a failed save, the creature takes 12 (2d10) fire damage, or half as much on a successful save.

Stairway to Pain CR 4

Simple Mechanical Trap

Appearance A set of wooden stairs leading up at a steep angle, at least 20 feet long.

Trigger A creature steps on the second step from the top.

Detection A successful DC 13 Wisdom (Perception) check reveals the trap.

Disarming or Destroying A successful DC 12 Dexterity check using thieves’ tools disables it. The trap can be destroyed by damaging the triggering step. This step has an AC of 8 and 10 hits points. If it is not destroyed in a single successful hit, it will activate the trap.

Damage and Effects When a creature steps on the “trigger step”, which is the second step from the top, the trap activates and every step on the stairs rotates and reveals razor-sharp blades mounted on them. Each step is now at an angle causing every creature to slide down the stairs, taking damage from each individual set of blades. The amount of damage varies by creature position.

Creatures in the bottom 5 feet of the stairs take no damage as they jump off the stairs.

Creatures above take 3 (1d6) slashing damage per 5 feet that they slide down and do not ignore the last 5 feet (on a typical set of stairs, that is 12 (4d6) slashing damage for sliding 20 feet down). The creatures must make a DC 12 Dexterity saving throw taking full damage on a failed save, or half as much damage on a successful one.

As soon as there are no more creatures on the stairs, the trap resets.

Dead Herring CR 4

Simple Mechanical Trap

Appearance A corpse lies rotting on the floor. At first glance, it appears to be garbed in fine quality clothing and the hilt of a long sword sticks out from underneath the body.

Trigger Jostling the body to loot or move it causes the dagger concealed under the body to slice open the bladder, releasing the poison.

Detection A successful DC 15 Wisdom (Perception) check notices the unusual angle at which the body is resting — almost as though it is posed.

Disarming or Destroying A successful DC 13 Dexterity check disarms the trap as the hero prevents the alchemical reagents from mixing. Anyone using alchemist’s supplies to disarm the trap gains advantage on the check.

Damage and Effects When the liquid alchemical component seeps from its container, it mixes with the powdered alchemical component on the floor below it and produces poisonous gas fumes. All creatures within a 15-foot-radius of the corpse must make a DC 13 Constitution saving throw.

On a failed save, the creature takes 16 (4d6) poison damage and is poisoned for 1 hour. On a successful save, the creature takes half as much damage and is not poisoned.

Sandwiched In Stone CR 4

Simple Mechanical Trap

Appearance An unlit 10-foot long by 5-foot wide underground hallway with a closed door at the end. The walls and floor of this hallway are made of rough, unworked stone. The unworked nature of the floor results in uneven areas of elevation and occasional small rocks dotting the path— the floor is difficult terrain.

Trigger Touching and turning the unlocked door’s handle.

Detection A successful DC 10 Wisdom (Perception) check reveals the slight smell of rotting garbage tinged with sulfuric acid typical of crawler mucus coming from the door handle. Additionally, a successful DC 13 Wisdom (Perception) check reveals thin tracks embedded in the natural stone ceiling and floor that run from both sides of the walls into the center of the room.

Disarming or Destroying A successful DC 10 Dexterity check allows a creature to wipe the carrion crawler mucus off the door handle without poisoning itself. A successful DC 15 Dexterity check using thieves’ tools allows the hero to jamb the tracks to keep the crushing stones at bay.

Damage and Effects A creature subjected to the poison must succeed on a DC 13 Constitution saving throw or be poisoned for 1 minute. The poisoned creature is paralyzed. The creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

As the door handle turns, 2-foot sections of wall (one on each side of the hall) slide along the tracks and slam together in the center of the hallway, crushing any creature standing in front of the door before retracting and resuming their original position. A mobile (non-paralyzed) creature that is standing in front of the door when this occurs can make a DC 10 Dexterity saving throw. The creature takes 22 (4d10) bludgeoning damage on a failed save, or half as much on a successful save.

Bard’s Bane CR 5

Simple Mechanical Trap

Appearance A finely crafted harp.

Trigger One string is off-key, and when its hollowedout tuning head is turned, the poison dust stored within is released.

Detection Because the poison dust is minuscule in size and weight and it is concealed within the tuning head, it is very difficult to detect.

A successful DC 20 Wisdom (Perception) or Intelligence (Investigation) check reveals a pinsized hole in the tuning head.

Disarming or Destroying A successful DC 10 Dexterity check using thieves’ tools will plug the hole and keep the dust from contaminating the harp.

Damage and Effects Once the trap is triggered, a few particles of poison dust (invisible to the naked eye) trickle down and coat the out-of-tune string. The poison remains potent until it is absorbed by contact with skin. When the string is plucked, the player of the harp must make a DC 15 Constitution saving throw. On a successful save, the creature takes 22 (4d10) necrotic damage or half as much on a failed save. The tuning head holds one dose of poison.

Spear Trap CR 5 — 6

Simple Mechanical Trap

Appearance Two lattice works made from spears spring from either side of a corridor when a beam of light is crossed.

Trigger A creature or object that’s Small or bigger passed through a beam of light.

Detection A successful DC 13 Wisdom (Perception) check reveals the presence of the trap, and that it’s activated by moving through the beam of light.

Disarming or Destroying A successful DC 15 Dexterity check using thieves’ tools disarms the trap. Anyone without thieves’ tools can attempt to disarm the trap, but they have disadvantage when doing so.

Failing the check triggers the trap.

Damage and Effects When triggered, the spears shoot out from either side, with 5 (1d10) spears attacking the triggering creature. Each spear makes a melee attack with a +8 bonus. The triggering creature takes 4 (1d8) piercing damage from each spear that hits.

Some of these traps are poisoned (adding 1 to the CR), in which case any creature hit must succeed on a DC 15 Constitution saving throw, taking 11 (2d10) poison damage on a failed save, or half as much damage on a successful one.

The trap resets on the following round.

GM’s Note: This is the trap you see on the front of this book.

Suffocating Room CR 5

Simple Mechanical Trap

Appearance An underground complex where the rooms are carved into the stone. The door to a 15-foot square library stands open. A rocking chair, a bearskin rug, and a pedestal with a pipe, a pewter goblet, and an empty glass decanter resting upon it occupy the center of the room.

The walls to the right and left and opposite the door are covered from floor to ceiling with bookcases packed with books.

Trigger When the heavy pewter chalice is moved, the switch that it depresses will pop up and trigger the air removal trap sequence.

Detection A successful DC 15 Wisdom (Perception) or Intelligence (Investigation) check reveals scuff marks on the floor just inside the room’s threshold in front of the door. If a creature examines the bookcase behind the books, a successful DC 15 Intelligence (Investigation) check reveals numerous pinhead-sized holes bored into the wooden bookcase that continue through the stone wall behind it.

Disarming or Destroying A successful DC 15 Dexterity check allows a creature to substitute an appropriately weighted object for the chalice so that the switch remains depressed, keeping the trap from triggering. Alternatively, a successful DC 10 Dexterity check using thieves’ tools made in conjunction with a DC 15 Intelligence (Investigation) check to find and plug all of the tiny holes will keep the air from being sucked out of the room.

Damage and Effects As the trigger switch activates, a panel of the stone wall to the left of the door slides in front of the door making an airtight seal and the mechanisms hidden within the walls simultaneously suck the air from the room. It takes 1 minute before all the air is sucked from the room. At that time, creatures in the room are subject to suffocation.

A creature can hold its breath for a number of minutes equal to 1 + its Constitution modifier (minimum of 30 seconds). When a creature runs out of breath, it can survive for a number of rounds equal to its Constitution modifier (minimum of 1 round). At the start of its next turn, it drops to 0 hit points and is dying, and it can’t regain hit points or be stabilized until it can breathe again.

The stone panel barring the exit has an AC 17 and 510 hit points. It has immunity to cold, fire, poison, psychic, radiant, slashing, and thunder damage and resistance to necrotic damage.

Swinging Blades CR 5

Simple Mechanical Trap

Appearance Large blades, shaped like crescent axes, swing like pendulums across a corridor, cutting any creatures caught in it to shreds.

Trigger Activated by pulling a lever or by stepping on a pressure plate in the middle of the area of effect, attacking any creatures in an area 10 feet ahead and behind the activating creature.

Detection A successful DC 15 Wisdom (Perception) check reveals the location of the lever, which is normally somewhat out of sight (but normally within 100 feet) of the pressure plate.

Disarming or Destroying A successful DC 15 Dexterity check using thieves’ tools disables the lever (if the person attempting it can reach the lever) or the pressure plate.

Damage and Effects All Medium or larger creatures within a 5-footwide and 20-foot-long area must make a DC 15 Dexterity saving throw or take 14 (4d6) slashing damage on a failed save, or half as much damage on a successful one. The damage continues each round following activation unless the trap is turned off or disabled.

If triggered by the pressure plate, the area of effect is centered on the pressure plate itself.

Camouflaged Pit Trap

Simple Mechanical Trap

Source DiFP

This pit has a cover constructed to resemble the floor around it. When a creature steps on the cover, it swings open causing the intruder to spill into the pit below, a ten foot fall that inflicts 1d6 bludgeoning damage.

A successful DC 15 Wisdom (Perception) check discerns the strange lack of foot traffic over the section of the floor and discovers the trap. Once discovered, it can only be disarmed by using something to wedge the trapdoor in such a way that prevents it from opening, whether a simple iron spike hammered between door and floor, or the use of arcane lock or similar magics.

Dumbwaiter Disaster CR 6

Simple Mechanical Trap

Appearance A set of muddy footprints belonging to a barefoot humanoid leads up and into a dumbwaiter but the dumbwaiter is currently empty. The dumbwaiter is large enough to accommodate a Small creature and the ropes for operating it on either side are intact.

Trigger Raising the two-story dumbwaiter.

Detection A successful DC 20 Wisdom (Perception) check reveals the remnants of a fine dust below the dumbwaiter where the base of the wall and the floor meet. The mechanism that houses and triggers the trap is behind the dumbwaiter box in the shaft and can’t be inspected by normal means while the dumbwaiter is on the first floor.

There is a 1-inch gap between the inner box and the outer wall of the shaft that would allow something minuscule to fit through such as an arcane eye. This strategy would allow the caster to look behind the inner box of the dumbwaiter and see the hook and the outline of the sliding door in the shaft that contains the hammer.

Disarming or Destroying When the inner box housing of the dumbwaiter is raised, a hook on the back of the box lifts a panel in the shaft that releases a spring-loaded hammer attached to a vial of blinding dust.

When the hammer slams down onto the shelf at the base of the dumbwaiter, the vial explodes, dispersing the blinding powder into the 5-foot space adjacent to the dumbwaiter. A successful DC 15 Dexterity check using thieves’ tools allows a creature to deconstruct the inner box housing of the dumbwaiter. Failing to disarm the trap triggers it.

Damage and Effects Any creatures in the 5-foot square adjacent to the dumbwaiter opening when the vial of blinding powder shatters must make a DC 13 Dexterity saving throw. A creature gains the blinded condition for 1 hour and takes 22 (4d10) slashing and piercing damage from tiny slivers of glass and chalk dust that coat their eyes and throat on a failed save. On a successful save, a creature takes half as much damage and is not blinded.

Roof Collapse CR 6

Simple Mechanical Trap

Appearance An unstable section of the ceiling is held up with rudimentary supports.

Trigger A creature moves a tripwire stretched across the ground between two support beams that are set very loosely, dislodging them.

Detection A successful DC 10 Wisdom (Perception) reveals the tripwire.

Disarming or Destroying A successful DC 15 Dexterity check using thieves’ tools cuts or disables the trip wire safely (the person making the check can reset the trap if they wish). Anyone with an edged weapon or tool can attempt the check, but they have disadvantage when doing so. Failing the check triggers the trap.

Damage and Effects When triggered, the ceiling collapses and any creature in the area (typically a 20-foot deep area that’s as wide as the room or corridor) beneath the unstable ceiling must attempt a DC 15 Dexterity saving throw, taking 22 (4d10) bludgeoning damage on a failed save, or half as much damage on a successful one. Once the trap is triggered, the floor of the area is filled with rubble and becomes difficult terrain.

GM’s note: Some of these traps drop far more debris than normal, as they are intended to collapse the tunnel, blocking off any entry completely. These traps deal 44 (8d10) bludgeoning damage on a failed save, or half as much on a successful one. When triggered, the area under the collapsed ceiling becomes impassable terrain. This version of the trap has a CR of 8.

This particular trap can also be used to simulate natural hazards such as mineshaft cave-ins or tumbling rocks on a mountainside.

Rust Dust CR 7

Simple Mechanical Trap

Appearance An underground cavern.

Trigger A trip wire strung between two boulders is rigged to release a net overhead.

Detection A successful DC 15 Wisdom (Perception) check reveals the trip wire and the net.

Disarming or Destroying A successful DC 15 Dexterity check using thieves’ tools disables the trip wire without causing the net to drop.

Damage and Effects The net is coated with rust dust and covers a 10-foot-by-10-foot area centered on the trip wire. Any creature within this area must succeed on a DC 15 Dexterity saving throw or be restrained.

Rust dust affected any nonmagical ferrous metal items worn or carried such as armor, shields, weapons, etc, automatically suffer a penalty at the start of every round that a creature is restrained in the net. Armor and shields suffer a permanent and cumulative -1 penalty to the AC they provide. Armor reduced to an AC of 10 is destroyed. A shield that drops to a +0 bonus is destroyed. Weapons take a permanent and cumulative -1 penalty to damage rolls. If a weapon’s penalty drops to -5, the weapon is destroyed.

Using an action to make a DC 10 Strength (Athletics) check successfully frees a creature from the net. Dealing at least 5 points of slashing damage (AC 10) to the net where it is in contact with a creature, frees the creature, though a metal weapon used for this purpose suffers the -1 penalty even if it’s being used by a creature outside of the net.

Rolling Boulder CR 10

Simple Mechanical Trap

Appearance A narrow tunnel, just over 10 feet wide, with a trapdoor in the ceiling from which rolls a 10- foot diameter boulder, crushing everything in its path.

Trigger When more than 20 pounds of weight is placed on the pressure plate.

Detection A successful DC 15 Wisdom (Perception) check reveals the pressure plate and the trapdoor in the ceiling or the streaks on the walls or floor where the boulder has passed by previously.

Disarming or Destroying Disarming the trap can be done by jamming a spike under the pressure plate or similar.

This can be done with a DC 15 Dexterity check. If using thieves’ tools or you have the Stonecunning racial ability, you gain advantage on the check. If it fails, you automatically trigger the trap.

Damage and Effects When activated every creature in the path of the boulder must make an Initiative check. The boulder rolls initiative with a +8 bonus, and on its turn it moves 60 feet in a straight line away from the trapdoor. The boulder can move through creatures’ spaces, and creatures can move through its space, treating it as difficult terrain.

Whenever the boulder enters a creature’s space or a creature enters its space while it’s rolling, that creature must succeed on a DC 15 Dexterity saving throw or take 55 (10d10) bludgeoning damage and be knocked prone.

The boulder stops when it hits a wall or similar barrier and cannot go around corners, but it can do gentle curving turns if the walls are built to guide such movement.

As an action, a creature within 5 feet of the boulder can attempt to slow it down with a DC 20 Strength (Athletics) check. On a successful check, the boulder’s speed is reduced by 15 feet and the damage is reduced by 11 (2d10).

If the boulder’s speed is reduced to 0, it stops moving and is no longer a threat, though it may still block the entrance to the area behind it.

GM’s Note: Some trap makers use a hollow steel ball instead of a stone boulder. This is fitted with sharpened spikes that retract once enough weight is on them (more than 1,000 pounds). These spikes deal a further 22 (4d10) slashing damage to anyone in the boulder’s path. This damage is not reduced by a successful Dexterity check (this increases the trap’s CR to 12).

Raining Fire & Acid CR 14

Simple Mechanical Trap

Appearance An unlit hallway that is 40-feet long by 10-feet wide with a 25-foot high ceiling. Its floor tiles are made from alternating quartzite and granite tiles, forming a checkerboard pattern, and its walls consist of roughly-worked stone blocks with significant natural texture.

Trigger Twenty feet into the hallway, both 5×5 foot tiles in that line of the floor pattern act as pressure plates that will activate when 20 pounds of pressure is applied to them.

Detection A creature studying the ceiling will notice a cloth (camouflaged to appear as the stone ceiling) stretched across the ceiling with a successful DC 15 Wisdom (Perception) check.

A creature studying the flooring at 20 feet into the hallway will notice the two pressure plates with a successful DC 15 Wisdom (Perception) check.

Disarming or Destroying A successful DC 17 Dexterity check using thieves’ tools will disarm the trap as the hero uses wedges to keep the pressure plates from depressing.

Damage and Effects When the pressure plates activate, they release spring-loaded knives in the ceiling that cut the strings which secure the camouflaged cloth stretched across the ceiling. As the lines holding the camouflaged cloth are cut, the hidden glass bottles of alchemical reactants that were sitting on the cloth plummet to the floor. When the glass shatters and the chemical compounds mix, fire and acid bombs explode across the entire hall. Creatures in the area of effect must make a DC 17 Dexterity check.

On a failed save, a creature takes 14 (4d6) fire damage, 14 (4d6) acid damage, and 14 (4d6) piercing damage, or half as much on a successful save.

Snake Room CR 8

Complex Mechanical Trap

Appearance An empty room, 10-foot-by-10-foot, with two doors and no ornamentation. Dozens of slightly indented holes can be seen along the top of each of the four walls.

Trigger A minimum of two creatures enter the room, triggering the pressure plate underneath the room.

The doors lock when triggered by the pressure plate, after which the room floods with 4 poisonous snake swarmsMM. These swarms fill up every available space in the room, allowing them to attack any creature in the room.

This trap must be reset manually, such as by a druid using speak with animals.

Initiative The doors lock on initiative 20.

The snake holes open on initiative 15, and the swarms attack on initiative 15.

Detection A successful DC 15 Wisdom (Perception) check reveals the trap.

Active Elements Lock Doors: The door(s) to this room slam shut and are locked in place. This effect activates only once, the first time the trap is triggered.

Snake Holes: The snake holes open, allowing the swarms to flood in. This effect activates only once, the first time the trap is triggered.

Swarms: The poisonous snake swarm spends the first round filling up the room (and doing no damage).

Dynamic Elements The swarms attack each round after the first one, acting on initiative 15.

Constant Elements There are no constant elements to this trap.

Disarming or Destroying A successful DC 14 Dexterity check using thieves’ tools disables the trap by breaking the pressure plate. The doors are locked but can be opened with a DC 15 Dexterity check using thieves’ tools. The doors have an of AC 15 and 18 hit points and can be forced open with a DC 16 Strength (Athletics) check. Alternatively, the snakes can be calmed with a successful DC 18 Wisdom (Handle Animal). Anyone casting speak with animals gains advantage on this check.

Common Pit Trap

Mechanical Trap

Four basic pit traps are presented here.

Poison Darts

Mechanical Trap

When a creature steps on a hidden pressure plate, poison-tipped darts shoot from spring-loaded or pressurized tubes cleverly embedded in the surrounding walls. An area might include multiple pressure plates, each one rigged to its own set of darts.

The tiny holes in the walls are obscured by dust and cobwebs, or cleverly hidden amid bas-reliefs, murals, or frescoes that adorn the walls. The DC to spot them is 15. With a successful DC 15 Intelligence (Investigation) check, a character can deduce the presence of the pressure plate from variations in the mortar and stone used to create it, compared to the surrounding floor. Wedging an iron spike or other object under the pressure plate prevents the trap from activating. Stuffing the holes with cloth or wax prevents the darts contained within from launching.

The trap activates when more than 20 pounds of weight is placed on the pressure plate, releasing four darts. Each dart makes a ranged attack with a +8 bonus against a random target within 10 feet of the pressure plate (vision is irrelevant to this attack roll). (If there are no targets in the area, the darts don’t hit anything.) A target that is hit takes 2 (1d4) piercing damage and must succeed on a DC 15 Constitution saving throw, taking 11 (2d10) poison damage on a failed save, or half as much damage on a successful one.

Poison Needle

Mechanical Trap

A poisoned needle is hidden within a treasure chest’s lock, or in something else that a creature might open. Opening the chest without the proper key causes the needle to spring out, delivering a dose of poison.

When the trap is triggered, the needle extends 3 inches straight out from the lock. A creature within range takes 1 piercing damage and 11 (2d10) poison damage, and must succeed on a DC 15 Constitution saving throw or be poisoned for 1 hour.

A successful DC 20 Intelligence (Investigation) check allows a character to deduce the trap’s presence from alterations made to the lock to accommodate the needle. A successful DC 15 Dexterity check using thieves’ tools disarms the trap, removing the needle from the lock. Unsuccessfully attempting to pick the lock triggers the trap.

Poison Needle Trap

Source DiFP

Simple Mechanical Trap

A poisoned needle is hidden in the locking mechanisms of the chest. A successful DC 20 Wisdom (Perception) check allows a character to detect the presence of the trap, and a successful DC 15 Dexterity check using thieves’ tools disarms it. Attempting to pick the lock without first disarming the trap triggers the trap, whether the picking attempt is successful or not.

When the trap is triggered, the needle springs out, extending several inches out of the lock. A creature picking the lock takes 1 piercing damage and 11 (2d10) poison damage, and then must succeed at a DC 15 Constitution saving throw or be poisoned for 1 hour.

Collapsing Roof Trap

Mechanical Trap

This trap uses a trip wire to collapse the supports keeping an unstable section of a ceiling in place.

The trip wire is 3 inches off the ground and stretches between two support beams. The DC to spot the trip wire is 10. A successful DC 15 Dexterity check using thieves’ tools disables the trip wire harmlessly. A character without thieves’ tools can attempt this check with disadvantage using any edged weapon or edged tool. On a failed check, the trap triggers.

Anyone who inspects the beams can easily determine that they are merely wedged in place. As an action, a character can knock over a beam, causing the trap to trigger.

The ceiling above the trip wire is in bad repair, and anyone who can see it can tell that it’s in danger of collapse.

When the trap is triggered, the unstable ceiling collapses. Any creature in the area beneath the unstable section must succeed on a DC 15 Dexterity saving throw, taking 22 (4d10) bludgeoning damage on a failed save, or half as much damage on a successful one. Once the trap is triggered, the floor of the area is filled with rubble and becomes difficult terrain.

Crossbow Trap

Source TM

Mechanical Trap

When a creature steps on a pressure plate with more than 20 lbs. of force, or trips another type of proximity trigger, 1d6 crossbows make a ranged attack at +8 to hit at random creatures within a 10 foot by foot area around the trigger. A target that is hit takes 4 (1d8) piercing damage per hit.

The crossbows are hidden in the walls and usually concealed by wooden paneling. The DC to spot them is 16. Locating the trigger requires a DC 18 Intelligence (Investigation) check. The trap can be disabled by wedging the pressure plate or blocking the bolt holes.

Rolling Sphere

Mechanical Trap

When 20 or more pounds of pressure are placed on this trap’s pressure plate, a hidden trapdoor in the ceiling opens, releasing a 10-foot-diameter rolling sphere of solid stone.

With a successful DC 15 Wisdom (Perception) check, a character can spot the trapdoor and pressure plate. A search of the floor accompanied by a successful DC 15 Intelligence (Investigation) check reveals variations in the mortar and stone that betray the pressure plate’s presence. The same check made while inspecting the ceiling notes variations in the stonework that reveal the trapdoor. Wedging an iron spike or other object under the pressure plate prevents the trap from activating.

Activation of the sphere requires all creatures present to roll initiative. The sphere rolls initiative with a +8 bonus. On its turn, it moves 60 feet in a straight line. The sphere can move through creatures’ spaces, and creatures can move through its space, treating it as difficult terrain. Whenever the sphere enters a creature’s space or a creature enters its space while it’s rolling, that creature must succeed on a DC 15 Dexterity saving throw or take 55 (10d10) bludgeoning damage and be knocked prone.

The sphere stops when it hits a wall or similar barrier. It can’t go around corners, but smart dungeon builders incorporate gentle, curving turns into nearby passages that allow the sphere to keep moving.

As an action, a creature within 5 feet of the sphere can attempt to slow it down with a DC 20 Strength check. On a successful check, the sphere’s speed is reduced by 15 feet. If the sphere’s speed drops to 0, it stops moving and is no longer a threat.

Scything Blade

Source TM

Mechanical Trap

Typically released by a trip wire, the scything blade can also be swung by a suit of armor. When the trigger is released, the scythe makes a melee weapon attack against a creature within 5 feet at +6 to hit. On a successful hit, it does 6 (1d8 + 2) slashing damage.

The trip wire can be noted with a DC 14 Wisdom (Perception) check and the trap can be disarmed by carefully cutting the wire. This requires a DC 12 Dexterity check and failing the check by five or more triggers the trap.

Swinging Block

Source TM

Mechanical Trap

When, after placing more than 20 lbs of force on a pressure plate, a creature removes its weight from the plate, a large stone block swings across on metal chains. Any creature within 5 feet of the trigger must make a DC 15 Dexterity saving throw. On a failed saving throw, the creature takes 21 (6d6) bludgeoning damage. A creature that is moving normally feels the plate shift with a DC 18 Wisdom (Perception) check. If a creature is dashing when it steps on the plate, it has disadvantage on the check.

Disarming the trap once the trigger is detected requires a DC 18 Dexterity check with thieves’ tools.

Pit with Bees

Source RGG:DST

Mechanical Trap

Swarming Pit Traps: The stone stoop in front of my door contains a pit perfectly positioned so that anyone fiddling with my lock falls into it. You might scoff at the basic pit trap for being too commonplace for a sorcerer of my caliber, and you’d be correct. I supplement the common pit trap with hives of aggressive bees to bedevil the trespassers, stinging them to death while distracting them so much they can’t climb out. You can build hives into the walls of your pit to ensure a vigorous swarming, or you can prepare an enchantment to magically summon tenacious bees of an extraplanar origin.

The stone stoop covers a pit that’s 10 feet square, 10 feet deep, and full of swarming bees. A successful DC 11 Wisdom (Perception) check discerns the absence of foot traffic over the stoop. A successful DC 11 Intelligence (Investigation) check is necessary to confirm that the stoop is actually the cover of a pit.

When anyone steps on the stoop, it swings open like a trapdoor, causing the intruder to spill into the pit below. A creature falling into the pit must succeed on a DC 10 Dexterity saving throw or be swarmed by bees, taking 2 (1d3) piercing damage immediately. Creatures entering the pit thereafter must also succeed at this saving throw or become swarmed. A creature swarmed by bees must make another saving throw at the start of each subsequent round. Failure means the creature takes another 2 (1d3) piercing damage that round; success means the bees have stopped swarming the creature, who takes no further damage. A creature taking damage automatically ends the swarming by jumping into enough water to douse themselves, being subject to a moderate or stronger wind, or taking at least 3 points of damage from a damaging area effect. Rolling on the ground or smothering the creature with a cloak or similar permits the creature another Dexterity saving throw with advantage.

Once the pit trap is detected, an iron spike or similar object can be wedged between the stoop and the surrounding ground in such a way as to prevent the cover from opening, thereby making it safe to cross. The cover can also be magically held shut using the arcane lock spell or similar magic.

Pit with Yellowjackets

Source RGG:DST

Mechanical Trap

Swarming Pit Traps: The stone stoop covers a pit that’s 10 feet square, 20 feet deep, and full of swarming yellowjackets. A successful DC 15 Wisdom (Perception) check discerns the absence of foot traffic over the stoop. A successful DC 15 Intelligence (Investigation) check is necessary to confirm that the stoop is actually the cover of a pit.

When anyone steps on the stoop, it swings open like a trapdoor, causing the intruder to spill into the pit below. A creature falling into the pit must succeed on a DC 13 Dexterity saving throw or be swarmed by yellowjackets, taking 5 (2d4) piercing damage immediately. Creatures entering the pit thereafter must also succeed at this saving throw or become swarmed. A creature swarmed by yellowjackets must make another saving throw at the start of each subsequent round. Failure means the creature takes another 5 (2d4) piercing damage that round; success means the yellowjackets have stopped swarming the creature, who takes no further damage. A creature taking damage automatically ends the swarming by jumping into enough water to douse themselves, being subject to a moderate or stronger wind, or taking at least 6 points of damage from a damaging area effect. Rolling on the ground or smothering the creature with a cloak or similar permits the creature another Dexterity saving throw with advantage.

Once the pit trap is detected, an iron spike or similar object can be wedged between the stoop and the surrounding ground in such a way as to prevent the cover from opening, thereby making it safe to cross. The cover can also be magically held shut using the arcane lock spell or similar magic.

Pit with Murder Hornets

Source RGG:DST

Mechanical Trap

Swarming Pit Traps: The stone stoop covers a pit that’s 10 feet square, 20 feet deep, and full of swarming yellowjackets. A successful DC 15 Wisdom (Perception) check discerns the absence of foot traffic over the stoop. A successful DC 15 Intelligence (Investigation) check is necessary to confirm that the stoop is actually the cover of a pit.

When anyone steps on the stoop, it swings open like a trapdoor, causing the intruder to spill into the pit below. A creature falling into the pit must succeed on a DC 15 Dexterity saving throw or be swarmed by murder hornets, taking 10 (4d4) piercing damage immediately. Creatures entering the pit thereafter must also succeed at this saving throw or become swarmed. A creature swarmed by murder hornets must make another saving throw at the start of each subsequent round. Failure means the creature takes another 10 (4d4) piercing damage that round; success means the murder hornets have stopped swarming the creature, who takes no further damage. A creature taking damage automatically ends the swarming by jumping into enough water to douse themselves, being subject to a moderate or stronger wind, or taking at least 12 points of damage from a damaging area effect. Rolling on the ground or smothering the creature with a cloak or similar permits the creature another Dexterity saving throw with advantage.

Once the pit trap is detected, an iron spike or similar object can be wedged between the stoop and the surrounding ground in such a way as to prevent the cover from opening, thereby making it safe to cross. The cover can also be magically held shut using the arcane lock spell or similar magic.

Pit with Hellwasps

Source RGG:DST

Mechanical Trap

Swarming Pit Traps: The stone stoop covers a pit that’s 10 feet square, 20 feet deep, and full of swarming yellowjackets. A successful DC 15 Wisdom (Perception) check discerns the absence of foot traffic over the stoop. A successful DC 15 Intelligence (Investigation) check is necessary to confirm that the stoop is actually the cover of a pit.

When anyone steps on the stoop, it swings open like a trapdoor, causing the intruder to spill into the pit below. A creature falling into the pit must succeed on a DC 16 Dexterity saving throw or be swarmed by hellwasps, immediately taking 25 (10d4) piercing damage and 14 (4d6) poison damage. Creatures entering the pit thereafter must also succeed at this saving throw or become swarmed. A creature swarmed by hellwasps must make another saving throw at the start of each subsequent round. Failure means the creature takes another 25 (10d4) piercing damage and 14 (4d6) poison damage that round; success means the hellwasps have stopped swarming the creature, who takes no further damage. A creature taking damage automatically ends the swarming by jumping into enough water to douse themselves, being subject to a moderate or stronger wind, or taking at least 16 points of damage from a damaging area effect. Rolling on the ground or smothering the creature with a cloak or similar permits the creature another Dexterity saving throw with advantage.

Once the pit trap is detected, an iron spike or similar object can be wedged between the stoop and the surrounding ground in such a way as to prevent the cover from opening, thereby making it safe to cross. The cover can also be magically held shut using the arcane lock spell or similar magic.

---

Magic Traps

Animated Fresco

Source TM

Magic Trap

A horrible fresco animates, causing all who can see it to make a DC 18 Wisdom saving throw. Those who fail drop whatever they are holding and become frightened for up to one minute. While frightened, a creature must take the dash action and move away from the fresco by the safest available route, unless there is nowhere to move. A creature who ends its turn in a location where it does not have line of sight to the fresco may make a DC 18 Wisdom saving throw, ending the effect on a success. After animating, the fresco cannot animate again for 24 hours.

Sphere of Annihilation

Magic Trap

Magical, impenetrable darkness fills the gaping mouth of a stone face carved into a wall. The mouth is 2 feet in diameter and roughly circular. No sound issues from it, no light can illuminate the inside of it, and any matter that enters it is instantly obliterated.

A successful DC 20 Intelligence (Arcana) check reveals that the mouth contains a sphere of annihilation that can’t be controlled or moved. It is otherwise identical to a normal sphere of annihilation.

Some versions of the trap include an enchantment placed on the stone face, such that specified creatures feel an overwhelming urge to approach it and crawl inside its mouth. This effect is otherwise like the sympathy aspect of the antipathy/sympathy spell. A successful dispel magic (DC 18) removes this enchantment.

Straw Needles

Source RGG:DST

Magic Trap

Several tiny, magical runes lie beneath the shaggy, durable material resembling straw that covers the tower’s exterior. The DC to spot a rune is 16. A spell or other effect that can sense the presence of magic, such as detect magic, reveals the rune and its aura of evocation magic. A successful DC 11 Intelligence (Arcana) check when examining a rune intuits that it creates magical backlash when the tower is attacked.

When a creature within 60 feet attacks the tower exterior, the rune magically launches three straw needles at the attacker. Each needle makes a ranged attack with a +4 bonus; vision is irrelevant to this attack roll. On a hit, the target takes 2 (1d4) piercing damage and must make a DC 11 Constitution saving throw, taking 4 (1d8) force damage on a failed save, or half as much damage on a successful save. The trap immediately resets, and thus launches a trio of needles after each attack on the tower exterior.

A successful dispel magic (DC 13) cast on a rune destroys it, but if the rune isn’t successfully dispelled, it launches its needles as though the dispel magic were an attack.

Straw Darts

Source RGG:DST

Magic Trap

Several tiny, magical runes lie beneath the shaggy, durable material resembling straw that covers the tower’s exterior. The DC to spot a rune is 16. A spell or other effect that can sense the presence of magic, such as detect magic, reveals the rune and its aura of evocation magic. A successful DC 13 Intelligence (Arcana) check when examining a rune intuits that it creates magical backlash when the tower is attacked.

When a creature within 60 feet attacks the tower exterior, the rune magically launches three straw darts at the attacker. Each dart makes a ranged attack with a +7 bonus; vision is irrelevant to this attack roll. On a hit, the target takes 2 (1d4) piercing damage and must make a DC 14 Constitution saving throw, taking 5 (1d10) force damage on a failed save, or half as much damage on a successful save. The trap immediately resets, and thus launches a trio of darts after each attack on the tower exterior.

A successful dispel magic (DC 14) cast on a rune destroys it, but if the rune isn’t successfully dispelled, it launches its darts as though the dispel magic were an attack.

Straw Arrows

Source RGG:DST

Magic Trap

Several tiny, magical runes lie beneath the shaggy, durable material resembling straw that covers the tower’s exterior. The DC to spot a rune is 18. A spell or other effect that can sense the presence of magic, such as detect magic, reveals the rune and its aura of evocation magic. A successful DC 13 Intelligence (Arcana) check when examining a rune intuits that it creates magical backlash when the tower is attacked.

When a creature within 60 feet attacks the tower exterior, the rune magically launches three straw arrows at the attacker. Each arrow makes a ranged attack with a +7 bonus; vision is irrelevant to this attack roll. On a hit, the target takes 3 (1d6) piercing damage and must make a DC 15 Constitution saving throw, taking 16 (3d10) force damage on a failed save, or half as much damage on a successful save. The trap immediately resets, and thus launches a trio of arrows after each attack on the tower exterior.

A successful dispel magic (DC 15) cast on a rune destroys it, but if the rune isn’t successfully dispelled, it launches its arrows as though the dispel magic were an attack.

Straw Spears

Source RGG:DST

Magic Trap

Several tiny, magical runes lie beneath the shaggy, durable material resembling straw that covers the tower’s exterior. The DC to spot a rune is 20. A spell or other effect that can sense the presence of magic, such as detect magic, reveals the rune and its aura of evocation magic. A successful DC 13 Intelligence (Arcana) check when examining a rune intuits that it creates magical backlash when the tower is attacked.

When a creature within 60 feet attacks the tower exterior, the rune magically launches three straw spears at the attacker. Each spear makes a ranged attack with a +8 bonus; vision is irrelevant to this attack roll. On a hit, the target takes 4 (1d8) piercing damage and must make a DC 15 Constitution saving throw, taking 27 (5d10) force damage on a failed save, or half as much damage on a successful save. The trap immediately resets, and thus launches a trio of spears after each attack on the tower exterior.

A successful dispel magic (DC 16) cast on a rune destroys it, but if the rune isn’t successfully dispelled, it launches its spears as though the dispel magic were an attack.

Fire-Breathing Statue

Magic Trap

This trap is activated when an intruder steps on a hidden pressure plate, releasing a magical gout of flame from a nearby statue. The statue can be of anything, including a dragon or a wizard casting a spell.

The DC is 15 to spot the pressure plate, as well as faint scorch marks on the floor and walls. A spell or other effect that can sense the presence of magic, such as detect magic, reveals an aura of evocation magic around the statue.

The trap activates when more than 20 pounds of weight is placed on the pressure plate, causing the statue to release a 30-foot cone of fire. Each creature in the fire must make a DC 13 Dexterity saving throw, taking 22 (4d10) fire damage on a failed save, or half as much damage on a successful one.

Wedging an iron spike or other object under the pressure plate prevents the trap from activating. A successful dispel magic (DC 13) cast on the statue destroys the trap.

Fire Breathing Suit of Armor

Source TM

Magic Trap

When a creature comes within fifteen feet of the armor, the armor releases a 15-foot cone of fire. Each creature within the cone must make a DC 16 Dexterity saving throw. Those that fail take 17 (4d6) damage while those that succeed take half as much.

The trap recharges on a 5 or 6 on 1d6. A variant of this trap is a fireplace breathing sparks instead.

Drowning Tentacles CR 6

Complex Magic Trap

Appearance A magical sigil on the bucket is activated by being disturbed, summoning tentacles that attack any creatures adjacent to the well. They attempt to drag the hero down and drown them.

Trigger The hemp fibers of the rope are woven in a pattern that forms a magical sigil. When the windlass is operated to lower the bucket, the sigil is activated and the spell is completed.

Detection A successful DC 15 Wisdom (Perception) or Intelligence (Arcana) check reveals the magical sigil. Detect magic reveals an aura of conjuration magic on the rope.

Initiative The tentacles act on initiative 20.

Active Elements Three rubbery tentacles reach up from the water in the well and randomly attempt to grab a creature in a square adjacent to the well. A targeted creature must succeed on a DC 15 Dexterity saving throw or take 16 (4d6) bludgeoning damage and be restrained by the tentacle.

Dynamic Elements Once a tentacle has restrained a target, it will retract on the next round, dragging the target underwater. On all subsequent rounds, the target automatically takes 16 (4d6) bludgeoning damage until the tentacles disappear or the 227277 target frees itself from the tentacles (whichever comes first). A creature restrained by the tentacles can use its action to make a DC 15 Strength (Athletics) or Dexterity (Acrobatics) check (its choice). On a success, it frees itself.

Constant Elements While restrained by the tentacles, the grabbed creature is dragged into the well and starts to drown. While a creature can normally hold its breath for a number of minutes equal to 1 + Con bonus, due to the strangling nature and tossing and twisting from the tentacles, this is reduced to a number of rounds equal to 3 + Con bonus.

Disarming or Destroying Dispel magic (DC 15) destroys the sigil. A successful DC 16 Intelligence (Arcana) check also destroys the sigil as the hero snips the rope fibers, unraveling the sigil. Failing the check triggers the trap.

last for 1 minute, after which time they dissolve harmlessly into water. The tentacles can’t be dispelled with dispel magic and are immune to all forms of damage except cold. Taking 5 points of cold damage immobilizes a tentacle (which has AC 10 and 30 hit points) for 1 round which prevents it from squeezing a creature and grants the creature advantage on its Strength or Dexterity check made to free itself.

---

Mechanical AND Magic Traps

Divide & Conquer CR 6

Simple Magic Mechanical Trap

Appearance A metal chest secured with an average lock requiring a DC 10 Dexterity check using thieves’ tools to open.

Trigger The chest holds four ornate chalices which rest atop a false bottom. A successful DC 5 Wisdom (Perception) or Intelligence (Investigation) check reveals the false bottom. The top panel (or lid) of the false bottom is made of a thin sheet of lead. A magical insignia is penned on the underside of it. Opening the false bottom changes the orientation of the insignia from horizontal to vertical. This change in orientation triggers a teleportation spell.

Detection Because the insignia is inscribed on the inside of an object, it is not readily visible, so it cannot be detected until triggered. A successful DC 15 Wisdom (Perception) or Intelligence (Investigation) check reveals the magical insignia only if these checks are made in conjunction with magic. Detect magic does not function in this case because of the thin sheet of lead. If a creature that is aware of the lead sheet makes a successful DC 15 Intelligence (Arcana) check, they determine that a magical trap or valuable magic item may be underneath.

Disarming or Destroying Dispel magic (DC 16) destroys the insignia.

Damage and Effects One random creature in contact with the lead panel when the trap is triggered is teleported into a stone sarcophagus located in a different location within 100 feet. The sarcophagus can accommodate a Large or smaller creature.

Any creature that doesn’t fit these parameters is immediately shunted out of the coffin and suffers 22 (4d10) force damage. The stone panels of the sarcophagus are 4 inches thick.

The sarcophagus has 50 HP, a 17 AC, and resistance to acid and piercing damage. It has immunity to cold, fire, necrotic, poison, psychic, radiant, and slashing damage. A successful DC 20 Strength (Athletics) check will slide the stone cover off. A creature inside the sarcophagus suffers a -2 penalty on the check due to the cramped space. After 4 hours, air runs out in the sarcophagus and a creature inside begins to suffocate.

Fire Jets CR 4

Simple Magic Mechanical Trap

Appearance Holes in the walls or nearby statues show a slight bit of charring from heavy flames at some point in the past.

Trigger A creature steps on a hidden pressure plate or activation tile, releasing gouts of flame from the nearby holes (often camouflaged as the mouth of statues).

Detection A successful DC 15 Wisdom (Perception) reveals the pressure plate or activation tile.

Detect magic reveals an aura of evocation magic from the statues (though this only applies to the magical version of trap).

Disarming or Destroying A successful DC 15 Dexterity check using thieves’ tools cuts or disables the pressure plate for the mechanical trap. For the magical version of the trap a successful dispel magic (DC 13) cast on the statue or the activation tile destroys the trap.

Damage and Effects When activated by a weight of more than 20 pounds, the fire holes (mouth of the statues if such are present) release a 30-foot cone of fire.

Each creature in the fire must make a DC 13 Dexterity saving throw, taking 22 (4d10) fire damage on a failed save, or half as much on a successful one.

Screaming Book CR 6

Simple Magic Mechanical Trap

Appearance A tattered ledger or diary on the table. It has no title, but a pen and vial of ink rest on the table beside the book.

Trigger Exposing the magical inscription on the first page by opening the book.

Detection Detect magic reveals an aura of evocation magic around the book.

Disarming or Destroying Dispel magic (DC 13) destroys the magical inscription.

Damage and Effects A loud boom rips from the pages. All creatures within a 20-foot-radius must make a DC 15 Constitution saving throw. On a failed save, a creature takes 16 (4d6) thunder damage and is deafened for 1 hour. On a successful save, the creature takes half as much damage and is not deafened.

GM’s Note: This trap is often used to alert sentries posted nearby of the presence of intruders.

The Demon’s Gaze CR 7

Simple Magic Mechanical Trap

Appearance Two demonic statues line the walls with one on either side of the corridor. The statues do not face each other but are set 5 feet above one another, each staring into the wall on the other side. Solid blue beams emanate from the eyes of one, while solid red beams emanate from the other.

Trigger A creature passes through one of the beams.

Detection A successful DC 14 Wisdom (Perception) check reveals that where the blue beams hit the wall there is a smattering of ice. Where the red beams hit the wall, there is scorching from fire.

Disarming or Destroying The trap cannot be disarmed through physical means, but can (temporarily) be disarmed through the use of dispel magic (DC 15). This subdues the trap for an hour. A DC 17 Intelligence (Arcana) check reveals that the beams can be safely passed through if a creature touches both beams at once.

Damage and Effects Any creature passing through a beam must make a DC 14 Reflex saving throw. A target takes 8d6 damage on a failed save, or half as much damage on a successful one. The damage taken depends on the beam crossed: crossing the blue beam deals cold damage, crossing the red beam deals fire damage. If a creature passes through both beams at once, no damage is taken.

Diseased Darts CR 9

Simple Magic Mechanical Trap

Appearance A ceramic tile mosaic covers the north wall of a 20-foot-square room.

Trigger A living creature approaching within 5 feet of the mosaic.

Detection A DC 15 Wisdom (Perception) check reveals that the mosaic is tied to a trap, but not how. A successful DC 17 Intelligence (Arcana) check reveals that certain religious sects use rituals to imbue likenesses of their deities with magical power. Detect magic reveals an aura of divination and evocation magic on the mural. A successful DC 17 Intelligence (Religion) check will reveal that the mosaic is in the form of a deity of disease and pestilence. Detect magic reveals an aura of evocation magic on the centered on the mosaic.

Disarming or Destroying A successful DC 15 Intelligence (Arcana) check reveals that a hallow spell counteracts the ritual magic used to create these mosaics. Dispel magic (DC 16) destroys the mosaic.

Damage and Effects A creature with a good facet in their alignment that approaches within 5 feet of the mosaic will be targeted by a barrage of magical darts of force and disease that automatically strike. The target takes 49 (11d8) force damage and is afflicted with cackle fever. Once the trap is triggered, it must be reconsecrated to function again.

Fiery Portrait CR 10

Simple Magic Mechanical Trap

Appearance A high-quality painted portrait whose eyes follow anyone watching the painting. An inner glow illuminates the eyes, occasionally flaring as if firelight was reflected in them.

Trigger A creature walks within 5 feet of the portrait and looks it in the eyes.

Detection A successful DC 15 Wisdom (Perception) check reveals the trap. Detect magic reveals an aura of evocation magic on the portrait.

Disarming or Destroying The trap cannot be disabled, but destroying it is easy. It has AC 5 and 8 hit points and is vulnerable to slashing and fire.

Damage and Effects Any creature within line of sight of the portrait must make a DC 15 Dexterity saving throw as they are enveloped in a pillar of fire. Each creature takes 24 (8d6) fire damage on a failed save, or half as much on a successful one. Creatures that fail the saving throw also catch fire taking 3 (1d6) damage at the start of its turn until they or an ally take an action to douse the fire. Once the trap has been triggered, the person in the portrait fades from view and the trap becomes inactive. The person reappears an hour later, after which the trap becomes active once more.

Impaling Stalactite CR 10

Simple Magic Mechanical Trap

Appearance A natural, underground cavern has stalactites on the ceiling 50 feet above and stalagmites with loose rubble on the floor creating difficult terrain.

Trigger Stepping on a magical engraving carved into the floor, which is concealed under sand and pebbles, triggers the trap.

Detection A successful DC 17 Wisdom (Perception) or Intelligence (Arcana) check reveals the magical engraving. Detect magic reveals an aura of transmutation magic on the floor.

Disarming or Destroying Dispel magic (DC 16) destroys the magical engraving. A successful DC 17 Intelligence (Arcana) check also destroys the magical engraving as the hero chisels away at the engraving, successfully siphoning away its power without triggering it.

Damage and Effects As soon as a creature steps on the magical engraving, gravity is reversed in that 5-foot square and the triggering creature falls upward for 50 feet until it hits the ceiling. The creature can make a DC 15 Dexterity saving throw to avoid being impaled upon the stalactite directly above. On a successful save, the creature slams into the ceiling and takes 24 (6d6) bludgeoning damage. On a failed save, the creature takes the bludgeoning damage and an additional 12 (3d6) piercing damage as it is also impaled by a stalactite. Whether the creature is impaled or not, it immediately falls back down as the effect abruptly ends. The creature can make a DC 20 Dexterity (Acrobatics) check to roll with the fall. It takes 24 (6d6) bludgeoning damage on a failed save, or half as much on a successful one.

Mass Electrocution CR 10

Simple Magic Mechanical Trap

Appearance An unlit hallway, 5-feet wide by 100-feet long, has an area of flooring that is an inch lower than the rest. The first 10 feet on either end of the hallway is not depressed, leaving the rest of the hallway 1-inch lower than the standard floor level. A crack on the right hand wall allows brackish water to slowly seep onto the floor.

Another crack on the left hand side of the hall allows the water to drain, keeping the hall from flooding, but leaving the depressed area with 1 inch of constant standing water.

Trigger A creature approaches within 10 feet of the glyph of warding spell that is inscribed on the tile floor 50 feet into the hallway.

Detection A successful DC 5 Wisdom (Perception) or Intelligence (Investigation) check reveals the cracks and the uneven floor. Anyone making a successful DC 15 Wisdom (Perception) or Intelligence (Investigation) realizes that the water is actually coming in from the cracks, rather than draining out.

The glyph is inscribed on the floor under water and needs to be spotted ten feet away which adds to the difficulty of detecting the trap. A successful DC 17 Wisdom (Perception) or Intelligence (Arcana) check reveals the magical glyph. Detect magic reveals an aura of abjuration magic in a 10-foot radius of where the glyph is inscribed.

Disarming or Destroying Dispel magic (DC 17) destroys the glyph. A successful DC 17 Intelligence (Arcana) ability check also destroys the glyph as the hero unravels part of the magic pattern of the glyph.

Damage and Effects The glyph of warding was crafted using the explosive runes with the lightning option.

All creatures standing in the water when the glyph is triggered must make a Constitution saving throw DC 17. A creature takes 45 (10d8) lightning damage on a failed saving throw, or half as much damage on a successful one.

Mirage Menaces CR 12

Simple Magic Mechanical Trap

Appearance A hall or room filled with hundreds of mirrors.

When a creature enters, the door slams shut, revealing a mirror on the inside of it too.

Duplicates of the triggering creature then emerge from the mirrors, attacking it.

Trigger A creature stands in or walks past the center of the room.

Detection A successful DC 15 Wisdom (Perception) check reveals that the door will slam shut when a creature stands in the middle of the room, but not the rest of the nature of the trap.

Discovering this before it activates requires a successful DC 16 Intelligence (Arcana) check.

Detect magic reveals an aura of illusion magic on each of the mirrors.

Disarming or Destroying The trap cannot be disarmed through physical means, but can (temporarily) be disarmed through the use of dispel magic (DC 17). This subdues the trap for 24 hours.

The mirrors can be destroyed, but at least 10 mirrors must be destroyed before the mirrors cease functioning. The mirrors have AC 8 and 10 hit points. Any broken mirrors reform in 24 hours.

Damage and Effects When triggered, 5 doppelgangersMM appear from the mirrors, taking the exact shape of the triggering creature. These creatures attempt to slay the triggering creature, but if killed they simply vanish into smoke, and the mirror that they emerged from turns dark, showing a reflection of the triggering creature lying dead in a coffin.

Once all five creatures are killed, the Hall of Mirrors becomes inactive for 24 hours.

Caught Red-Handed CR 12

Simple Magic Mechanical Trap

Appearance A dressing room containing a vanity with a mirror and a cushioned bench. Several containers of makeup, a bottle of perfume, and a jewelry box rest upon the vanity. Three mannequins stand in various poses. Each mannequin has a wig on its head, a neckerchief at its throat, a bracelet on its wrist, and one or more rings (each with a different gemstone) on each hand.

Trigger Exposing the magical glyph inscribed on the mannequin’s finger by removing the ruby ring covering it.

Detection Because the glyph is inscribed on the finger under the ruby ring, it is not visible for inspection without moving the ring. An arcanist’s magic aura spell has been cast on the glyph to mask its magic, making it appear to be nonmagical.

GM’s Note: If a creature wants to make a visual inspection of the jewelry without handling it, A successful DC 20 Intelligence check reveals that the jewelry on display is costume jewelry.

Disarming or Destroying If dispel magic (DC 16) is cast on the trapped mannequin, it will automatically dispel the arcanist’s magic aura spell first, leaving the glyph active. A second dispel magic (DC 16) is required to dispel the glyph.

If a creature uses detect magic again, they notice that there is still an aura of abjuration magic emanating from the finger.

Damage and Effects As the ruby ring is taken off the mannequin’s finger a disintegrate spell targets the creature triggering the trap. The targeted creature must make a DC 16 Dexterity saving throw. On a failed save, the target takes 75 (10d6 + 40) force damage. The target is disintegrated if this damage leaves it with 0 hit points.

Curiosity Killed The Cat CR 15

Simple Magic Mechanical Trap

Appearance A closed, sturdy, iron door.

Trigger A creature’s reflection in the mirror (mounted on the wall behind the false door) triggers the magical trap.

Detection A successful DC 20 Intelligence (Investigation) check reveals that a thin piece of paper pushed under the door is stopped by an obstacle which indicates something unusual, but not the exact nature of the trap. Detect magic can’t reveal the magical inscription on the back of the mirror because it is located behind the 1-inch thick iron door. If a creature employs magic that allows them to see through objects in conjunction with a successful DC 20 Wisdom (Perception) check, they discover a magical inscription on the back of the mirror. They will also see that there is only stone, but no room behind the false door.

Disarming or Destroying Destroying the mirror is a simple matter of smashing it, but it must be done without showing your reflection. The mirror has an AC of 5 and 8 hit points. Dispel magic (DC 18) destroys the trap.

Damage and Effects A feeblemind (DC 18) spell targets the first creature reflected in the mirror.

Wheel of Death CR 16

Complex Magic Mechanical Trap

Appearance A 20-foot circular room with a single 3-foot high pillar in the middle, on which is placed a darkgray stone.

Trigger 2 rounds after a creature steps into the room.

Detection A successful DC 18 Wisdom (Perception) check reveals that the room itself is trapped, and reveals grooves and scrapes along the walls.

Detect magic reveals an aura of transmutation magic on the stone.

Initiative The doors lock on initiative 20.

Each of the walls of blades acts on an initiative of 15.

The gravity stone in the middle of the room acts on an initiative of 5.

Active Elements Lock Doors: The door(s) to this room slam shut and are locked in place, requiring a DC 20 Dexterity check using thieves’ tools to open.

This effect activates only once, the first time the trap is triggered.

Damage and Effects Two rounds after a creature enters the room the door(s) slam shut and 4 longswords emerge from each of the walls. The walls then start spinning at great speeds, while the dark stone in the middle starts emitting pulses that push living creatures out towards the walls.

This continues for 5 rounds, or until every creature in the room is dead, or the trap is disabled or destroyed, depending on what comes first.

GM’s note: Cleaning the room or disabling the trap for an owner is a simple matter of putting a cloth infused with lead over the stone in the room.

Wall Blades: The walls of blades start spinning up to speed. The longswords attack anyone within 5 feet of them. Each set of swords has a +10 bonus to the attack roll and deals 18 (4d8) slashing damage.

Gravity Stone: Each creature in the room must make a DC 18 Strength saving throw. On a successful save, the creature takes no damage and is moved 5 feet towards the walls. On a failed save, the creature is flung all the way out, ending up adjacent to the nearest wall.

Dynamic Elements Each round, for the next 4 rounds, the blades spin faster, increasing the damage by 1d8, to a max of 4d8.

Constant Elements Any creature that ends its turn within 5 feet of any of the walls are attacked as per the active Wall Blades.

Disarming or Destroying A successful DC 20 Dexterity check using thieves’ tools disables it. The trap can be destroyed by dealing 30 points of damage to it. It has an AC of 17. Each successful check disables one of the “wall blades”. Each of the 4 wall blades must be disabled or destroyed individually.

Alternatively, by succeeding on a DC 15 Intelligence (Arcana) check, the hero realizes that the trap can be disabled by putting a leadlined cloth over the gravity stone.

Dead Heads CR 4

Simple Magic Mechanical Trap

Appearance A corridor, 80-feet long by 5-feet wide by 15-feet high. There is a lit torch at the start and end of the corridor.

Trigger A pressure plate 50 feet down the corridor opens the hidden trapdoor in the ceiling and activates the magical rune inscribed underneath it.

Detection A successful DC 15 Wisdom (Perception) or Intelligence (Investigation) check will reveal the pressure plate on the floor or the trapdoor in the ceiling. Detect magic reveals a faint aura of necromantic magic around the edges of the pressure plate. Detect magic reveals an aura of necromancy magic emanating from the ceiling.

Disarming or Destroying A successful DC 15 Dexterity check using thieves’ tools will disarm the trap as the hero wedges the pressure plate in place. Dispel magic (DC 12) destroys the magical rune, but has no effect on the trapdoor.

Damage and Effects Necromantic magic imbues the twelve preserved heads hidden in the ceiling with a semblance of life for 1 round. As the trapdoor opens, the heads fall to the floor, attempting to bite the nearest creature on the way down.

If a creature is between 30 and 50 feet into the corridor, one falling head will attempt to bite it. Each head makes a melee attack with a +8 bonus. It deals 2 (1d4) piercing damage plus 9 (2d8) poison damage.

If the magical rune is dispelled but the trapdoor is still triggered, the twelve heads fall to the floor and all creatures 30 to 50 feet into the corridor must make a DC 10 Dexterity save or be struck by a falling head for 1 point of bludgeoning damage.

Greedy Fountain CR 4

Simple Magic Mechanical Trap

Appearance A functioning water fountain where gold coins can be seen at the bottom.

Trigger Any living creature that is adjacent to the fountain hears a magical suggestion in their mind.

Detection A successful DC 15 Wisdom (Perception), Intelligence (Investigation), or DC 15 Intelligence (Arcana) check reveals the presence of sigils painted onto the inside bowl of the fountain under the shallow water. Detect magic reveals auras of enchantment, illusion, and conjuration around the fountain.

Disarming or Destroying A DC 15 Intelligence (Arcana) check reveals that the trap can be destroyed by physically damaging the bowl of the fountain, which has an AC of 10 and 5 hit points, cracking and destroying the magical script. Dispel magic (DC 15) dispels the magical sigils.

Damage and Effects A creature adjacent to the fountain hears the following words (spoken in their native tongue) in their mind: “Place your weapons in the fountain.” If the creature can’t be charmed, it is immune to the effects. Otherwise, it must make a DC 16 Wisdom saving throw. On a failed save, the creature must immediately spend 1 round putting any handheld weapon(s) and up to two sheathed weapons it may have into the fountain. At the end of the round, any weapons the creature deposited in the fountain are teleported away to a locked chest within 100 feet.

The coins at the bottom of the fountain are illusory.

---

Haunts

Haunts, by their nature, have the Magic trait, as well as the Haunt trait.

Animated Objects Haunt

Magic Haunt

Source TM

Magic Haunt

When one or more creatures enter the trapped region, up to 11 small or 5 medium weapons animate and attack them. On initiative 10, each weapon moves up to 30 feet towards a target and makes a melee weapon attack against a target within 5 feet at +6 to hit. Small weapons do 5 (1d6 + 2) slashing or piercing (as appropriate) damage on a hit while medium ones do 8 (1d10 + 3). Each weapon has AC 14 and is destroyed if it takes 18 hit points of damage. They are immune to necrotic, poison, and psychic damage. Casting dispel magic on a weapon causes it to revert to an inanimate state for one hour.

Commanding Visage

Magic Haunt

Source TM

Magic Trap

When a creature approaches within 10 feet of this large stone visage, it commands the creature to drink a potion of poison lying on the pedestal. The target of the command must make a successful DC 16 Wisdom saving throw or attempt to comply with it. A creature that succeeds on the saving throw is immune from further commands from this face.

There is a 50% probability that the stone face has 100 gp gems for eyes.

Hypnotic Brazier

Source TM

Magic Haunt

This brazier may stand in something resembling an elaborate ritual chamber – with candles, diagrams, tapestries and idols. Its magical flames create a hypnotic pattern. Any creature that looks upon it must succeed on a DC 16 Wisdom saving throw or be hypnotized by the brazier. A hypnotized creature may attempt a new saving throw at the end of each its turns. Once it has succeeded on a saving throw, the creature is immune to the brazier’s hypnosis for 24 hours. A hypnotized creature makes every effort to get amidst the brazier’s flames as quickly as possible. Each round that a creature spends in the fire it takes 27 (6d8) fire damage. Dispel magic cast with a level 4 spell slot dampens the hypnotic pattern for 1 round, giving any creatures needing to make a saving throw advantage.

Disembodied Hands with Chilling Touch

Source TM

Magic Haunt

When a creature enters a room being guarded by this trap, a pair of spectral hands appear and target it. Up to six pairs of hands may appear, one per creature in the area. On initiative 20, the hands move up to 50 feet to follow their target as long as the target is within the room, and make a spell attack against their target if they are within 10 feet of the target.

The attack is made at +7 to hit. On a successful hit, the target takes 3 (1d6) cold damage and, on a failed DC 15 Constitution saving throw, loses 1 point of Strength until completing a long rest.

Disembodied Hands with Vampiric Touch

Source TM

Magic Haunt

When a creature enters a room being guarded by this trap, a pair of spectral hands appear and target it. Up to six pairs of hands may appear, one per creature in the area. On initiative 20, the hands move up to 50 feet to follow their target as long as the target is within the room, and make a spell attack against their target if they are within 10 feet of the target. The attack is made at +7 to hit. On a successful hit, the target takes 14 (4d6) necrotic damage and cannot regain hit points until the start of the next round.

Magic Mouth

Source TM

Magic Haunt

When a creature comes within 30 feet of the magic mouth, it cries loudly for help. Make three random monster checks. The magic mouth then becomes inactive for one hour. A variant of this trap also casts arcane lock on all exits, increasing the DC to break them down or unlock them by 10.

Malevolent Mirage

Source TM

Magic Haunt

A wondrous hypnotic illusion appears. Any creature seeing the illusion must make a DC 16 Wisdom saving throw or use its movement and make the dash action to enter its area. Within the area covered by the illusion may be spiked pits, fire, or any other form of dangerous area. The illusion can be seen through with a successful DC 18 Intelligence (Investigation) check.

The mirage could originate from an idol, fresco, statue, gemstone (1d3 x 100 gp), etc.

Moving Executioner Statue

Source TM

Magic Haunt

If a creature comes within 5 feet of the statue without depressing the bypass switch to disarm it, the statue makes a melee attack at +10 to hit against it. On a hit, the target takes 15 (2d6 + 8) slashing damage. The statue continues to make attacks as long as a target is within range and the statue has not been destroyed or disarmed. The bypass switch can be located with a successful DC 18 Wisdom (Perception) check. The statue is destroyed if it takes 25 points of damage. It has an AC of 15. The statue may guard a pedestal with small gemstones of little value, or stand in a room resembling a shrine or temple.

Rapid Rot

Source TM

Magic Haunt

A creature who touches the object protected by this trap must make a successful DC 14 Charisma saving throw or it and all objects it is wearing or carrying instantly age 1000 years. For most creatures, this means instant death, leaving only grey, moldy dust remaining. Detecting the trap requires a successful DC 18 Intelligence (Arcana) check. Once the trap has triggered, it cannot do so again for 24 hours.

Note: This trap is always linked to an item of great worth (1d6 x 500 gp), usually prominently displayed and surrounded by grim reminders of death and decay. E.g. a solid gold bowl in a room full of graven stone skulls, dust and moldy cobwebs, held by the statue of Death personified.

Room Full of Diseased Corpses

Magic Haunt

Source TM

The corpses all have slimy doom. The disease can be recognized with a successful DC 15 Wisdom (Medicine) check. The corpses may be just piled up, or placed elaborately in wooden thrones, hung on hooks, sitting in plush chairs or any other arrangement. They are usually moldy and putrid, but some (25% probability) possess 1d3 pieces of jewelry, value 2d8 x 10 gp. Finding any treasure requires a DC 14 Wisdom (perception) check (and probably touching the corpses).

---

Crumbling Ledge

Source Game Master’s Guide to Traps & Terrors

Natural Trap

This trap is an unstable dirt, rock, or stone ledge or outcropping overlooking a steep drop, such as a cliff or chasm. It is usually encountered in badlands, dungeons, hills, mines, mountains, and ruins.

Related Traps: Broken Bridge, Collapsing Roof, Sinkhole.

Trigger: This trap is triggered when 20 pounds or more of pressure is applied within 5 feet of the edge.

In addition, any area effect attacks or spells that deal acid, bludgeoning, fire, force, lightning, or thunder damage that hit creatures on, over, or around the ledge (or the ledge itself) also trigger the trap.

Spot: A successful DC 13 Perception check reveals the ledge might not be safe. A successful DC 15 Investigation check reveals just how unsafe it is without triggering the trap.

Disarm: N/A

Dimensions: 15 feet long by 15 feet width.

Number of Uses: One.

Reset: N/A

Effect: When triggered, the entire ledge vibrates and its outermost 5 foot portion crumbles. Depending on how close a creature is to the edge determines the effect:

• Within 5 Feet: Any creature within 5 feet of the edge must make a DC 17 Dexterity saving throw or fall (taking appropriate falling damage). On a success, it is now hanging onto roots, vines, scrub, or rock. It must make a DC 15 Strength saving throw to pull itself up over the ledge. On a success, it enters the nearest unoccupied square of stable terrain but is knocked prone in it.
• Within 10 Feet: Any creature within 10 feet of the edge must make a DC 13 Dexterity saving throw or fall. On a success, it is knocked prone into the nearest unoccupied square containing stable terrain.
• Within 15 Feet: Any creature within 15 feet of the edge must make a DC 10 Dexterity saving throw or lose its reaction as it steadies itself during the collapse.

Grabbing Onto Another Creature: If you are close enough to grab onto a creature in range that isn’t falling, resolve a grapple attack. If you succeed, you are holding onto the grappled creature. It must make a DC 15 Strength saving throw or be pulled off-balance by your weight so that you both fall off the ledge.

Options

If you’d like to customize this trap, choose from the options below.

Commanding View: Any ranged weapon or spell attack rolls that target creatures visible below the ledge gain a +2 bonus to hit. There is no modifier for targeting creatures either above the ledge or at roughly the same elevation (within +/- 10 feet).

Second Ledge: The GM can also rule there is a second, smaller ledge somewhere beneath this one that is stable and capable of supporting a Large or smaller creature’s weight, but which may have no easy way of escape. If there is a second ledge below, it is 1d3 x10 feet underneath it.

The falling creature must make a DC 15 Dexterity saving throw. If it succeeds, it lands safely on the second ledge but suffers 1d6 bludgeoning damage per 10 feet fallen, is knocked prone, and stunned until the end of its next turn. If it fails, it misses the second ledge and keeps falling. If the save fails its roll by 5 or more, it bounces off the second ledge, takes the bludgeoning damage and stunned effect, and keeps falling!

To be nice, or lead to a fun side quest, the GM can rule that the second ledge has a simple one-room cave or perhaps an entire cave complex attached to it…

Slippery: The bridge is wet from rain, snow, or slime. Increase all check and saving throw DCs on the bridge by +2.

Stable Ledge: To create a stable ledge instead, select the Commanding View option and modify this trap’s trigger so it only becomes a crumbling ledge if any area effect attacks or spells that deal acid, bludgeoning, fire force, lightning, or thunder damage that hit creatures on, over, or around the ledge (or the ledge itself)

Sympathetic Magic: All Air, Earth, Lightning, and Thunder magic cast on or within 15 feet of the ledge has its DC increased by +1 and deals an extra 1d4 damage of its type on a failed save. If the ledge overlooks water, or some other liquid (like acid or lava), or if it is cold out, then that magic gains the above bonuses as well.

Construction Time: N/A

Cost: N/A

Note: This trap first appeared in a different form as Chasm or Cliff in Extreme Encounters: Weather & Terrain: Earth. Earth is also collected in our Elemental Omnibus.

---

Ditch

Source Game Master’s Guide to Traps & Terrors

Difficult Terrain

A ditch is basically a contiguous series of shallow pits strategically dug by defenders to slow or injure infantry or cavalry. A ditch may be concealed by foliage and/or be filled with wooden stakes to impale creatures falling in. Unlike pits, ditches are always in the dirt and are built in lines (not necessarily straight ones) that can go on for hundreds of feet or even miles. Deeper ditches may be used as empty moats, mass graves, or trenches.

Related Traps: Hedgehog, Magic Landmine, Moat, Pit (Flooded), Pit (Hidden), Pit (Simple).

Trigger: Whenever a creature attempts to enter or pass over the ditch.

Spot: In bright light, an unconcealed ditch does not require a roll to spot. In dim light, an unconcealed ditch requires a successful DC 10 Perception check to spot in time, and in nonmagical darkness, the DC increases to DC 12. If the ditch is concealed, then the DC becomes 11 in bright light, DC 13 in dim light, and DC 15 in nonmagical darkness.

Disarm: N/A, short of filling it in.

Dimensions: A ditch is rarely more than 5 feet deep.

Number of Uses: Limitless, unless filled in.

Reset: N/A

Effect (General): A ditch counts as difficult terrain for all creatures from Tiny to Huge size who are using their land speed. Gargantuan creatures are immune to this effect, unless the GM rules otherwise (and the ditch in question must be really wide and deep).

Effect (vs. Infantry): Any creature of Large size or smaller that enters the ditch must make a running or standing long jump with a DC 13 Athletics or Acrobatics check to jump over it without falling in.

This assumes the ditch is not too wide for it to jump.

On a success, the creature clears the ditch and ends its movement in an unoccupied square on the opposite side within 5 feet of the ditch (or within 10 feet with a running start). If the check fails, the creature immediately ends its movement knocked prone in the ditch. It takes 1d6 bludgeoning damage if the ditch was 10 feet deep, or 1d3 if it was 5 feet deep. It takes an extra 1d8 piercing damage and is impaled and restrained if the ditch contains wooden stakes on the first round. It takes an extra 1d8 piercing damage every round at the end of its turn for as long as it remains impaled.

Unlike most impalings, the stakes in a ditch are rarely long enough to prevent the impaled creature from freeing itself. It may do so by spending all of its actions and losing its reaction on the round after it is impaled.

A creature attempting to climb up or down a ditch rather than jump it does not require a check unless the ditch contains stakes. If it does, then the creature must make a successful DC 10 Athletics or Acrobatics check to avoid slipping or tripping and impaling itself.

On a failure, it is knocked prone and impaled on the stakes. It can attempt to rise and free itself on its next turn.

Effect (vs. Mounts and Riders): If a rider directs its mount to charge and leap the ditch, the rider must make a DC 13 Animal Handling check to convince the mount to follow its command. Once the mount reaches the ditch, assuming it can logically do so, it must make a DC 13 Athletics or Acrobatics check to clear the barrier and land on the other side. If it succeeds, it does so safely and continues its movement (provided it still has some left). The rider must then make a DC 13 Athletics or Acrobatics check to remain mounted. If the check fails, the rider is dismounted and suffers 1d6 bludgeoning damage from the fall. If the mount fails, it suffers 4d6 bludgeoning damage. If this results in 12 or more points of damage, its leg is broken and it is useless as a mount. It must be either put out of its misery or magically healed to be ridden again. If the ditch contains stakes, the mount takes an extra 2d6+6 piercing damage in addition to the bludgeoning damage and is impaled and restrained.

The rider must make a DC 15 Athletics or Acrobatics check or be dismounted. If the save is failed by 5 or more, the rider suffers 2d6 piercing damage and is restrained in the saddle as its mount kicks and thrashes. Any enemies gain advantage on attacks against both mount and rider until they clear themselves of their impalement. They are allowed a new check each round until they do, but continue to take 1d6 piercing damage each round until they are free. If the rider’s check fails by less than 5, it is thrown clear of its mount and lands on the opposite side of the stakes, suffering 1d6 bludgeoning damage and being knocked prone in the process. If the rider makes its check, but its mount is impaled, the rider can choose to dismount safely on either side of the stakes and may take any remaining actions or reaction available.

Options

If you’d like to customize this trap, choose from the options below.

Fire Line: This ditch has been filled with flammable oil. It must be manually ignited by defenders as a reaction when hostile creatures approach and/or enter the ditch. The oil burns for 1 hour. Any creature that enters the ditch takes 1d10 points of fire damage in addition to any other effects. The creature continues to take this fire damage every round it remains inside the ditch, and continues to burn for 1d3 rounds after it exits (taking half damage).

This additional damage can be prevented if the creature chooses to become knocked prone, then use all its remaining actions and reactions that turn to roll around. This extinguishes the flames and prevents further damage.

Mass Grave: This tends to be a much deeper variant ditch dug to be filled with corpses, perhaps of those executed for cowardice in battle or as traitors, or simply to dispose of plague victims. These bodies may or may not be present. If they are, there is a chance one of them is still alive, either just barely and begging for help, or faking being dead by hiding under a real corpse. The bodies may also be diseased. Any creature touching a diseased corpse must succeed at a Constitution saving throw or be infected by whatever disease killed the creature. At minimum, this is a DC 11 save vs. sewer plague.

Military Trench: If your campaign setting includes firearms, the ditch might be a World War I-style trench garrisoned by infantry, complete with underground bunkers, command centers, and storerooms. Trenches are typically deeper than they are wide (with most being 10 feet deep and no more than 5-10 feet wide).

Trenches may have more than one path to connect different sections to each other, such as a connected ring or circle of rings.

A trench is designed to facilitate troop movement and is therefore not considered difficult terrain (unless it is partially flooded by rain or filled by snow).

Construction Time: This trap’s construction time is contingent on the length and depth of the ditch, as well as the available manpower or excavation magic.

Assume one day per 10-foot long, 5-feet deep section completed by a team of two Medium-size creatures with picks, shovels, and related gear. Employing an arcane or divine caster with excavation magic reduces the time and increases the dimensions by the available spells and however many times they need to be cast.

Cost: The cost is contingent on the number of picks, shovels, and daily rate of the diggers, plus the length and depth of the ditch. Assume 10 gp for a 100-foot straight, circular, or diagonal line with a 5-foot depth; or double that for a 50-foot straight, circular, or diagonal line with a 10-foot depth. Uneven, asymmetric lines or connected lines add to +50% to the cost regardless of length or depth. Excavation magic triples the cost.

---

Hedgehog (Difficult Terrain) This is a portable 10-foot “hedge” of wooden stakes, pikes, spears, or metal “jacks” (that resemble Large blunt caltrops) positioned on a battlefield or security checkpoint to deter cavalry, infantry, siege weapons, or beasts. Permanent versions may be found ringing hills or other defensive positions.

Whether temporary or permanent, most such positions consist of multiple hedgehogs with a narrow break to allow approved traffic, or to encourage enemies to move in a desired direction around or between them.

Related Traps: Ditch, Drawbridge, Magic Landmine.

Trigger: When a creature comes into contact with the hedgehog.

Spot: In nonmagical darkness, it requires a successful DC 12 Perception check to spot the hedgehog and recognize the danger if it is not concealed. No check is necessary in bright or dim light unless the hedgehog is concealed in some way (such as with foliage). When concealed. The DC is 12 in bright light, or DC 15 in dim light or nonmagical darkness.

Disarm: A hedgehog can be dragged away if left unguarded, but this requires two or more creatures with 13 or higher Strength scores, or at least one horse or oxen. Hedgehogs that aren’t metal can also be broken down into their individual components and carted away or destroyed.

Dimensions: A portable hedgehog is typically 10 feet long by 5 feet high and wide, but permanent larger/ longer ones exist, and may be as long as needed or the area allows.

Number of Uses: Limitless, unless moved away or destroyed.

Reset: N/A

Effect vs. Infantry (Spears/Pikes/Stakes Only): Any creature of Large size or smaller that enters a square containing a hedgehog must perform a running long jump by making a DC 17 Athletics or Acrobatics check to jump its barricade without being impaled. A standing long jump is impossible without magic like a jump spell. On a success, the creature clears the hedgehog (assuming it was physically possible for it to). The creature ends its movement in an unoccupied square on the opposite side that is adjacent to the hedgehog. If it fails, the creature immediately ends its movement and becomes impaled and restrained until freed by another creature. It takes 6d8+6 piercing damage on the first round, and 1d8 piercing damage every round after that (always at the end of its turn) for as long as it remains impaled.

A creature attempting to climb over a hedgehog rather than jump it must make a DC 13 Athletics or Acrobatics check instead. On a success, it clambers over and ends its movement in an unoccupied adjacent square to the hedgehog. On a failure, it gets stuck and knocked prone on top of and/or inside the hedgehog.

It can attempt to rise and free itself on its next turn. Any creature in or on top of the hedgehog treats it as difficult terrain.

Effect vs. Cavalry (Spears/Pikes/Stakes Only): If a rider directs its mount to charge or leap a hedgehog, the rider must make a DC 17 Animal Handling check with disadvantage to convince the mount to follow its command. Once the mount reaches the hedgehog, assuming it can logically do so, it must make a successful DC 17 Athletics or Acrobatics check to clear the barrier and land on the other side. The rider must then make a DC 17 Athletics or Acrobatics check to remain mounted. If the check fails, the rider is dismounted and suffers 1d6 bludgeoning damage from the fall, but clears the hedgehog. If the mount fails, it suffers 8d6+6 piercing damage and is impaled and restrained. The rider must make a DC 17 Athletics or Acrobatics check or be dismounted. If the check is failed by 5 or more, the rider suffers 2d8 piercing damage and is restrained in the saddle as the mount kicks and thrashes. Any enemies gain advantage on attacks against both mount and rider until they clear themselves of their impalement. They are allowed a new check each round until they do, but continue to take 1d8 piercing damage each round until they are free. If the rider’s check fails by less than 5, it is thrown clear of its mount and lands on the opposite side of the stakes (in an unoccupied square adjacent to the hedgehog). It takes 1d6 bludgeoning damage and is knocked prone. If the rider makes its check, but its mount is impaled, the rider can choose to dismount safely on either side of the stakes and may take any remaining actions or reaction available.

Effect (Jacks Only): A creature unwilling or unable to must either spend all its actions for the round crawling under or over the jack and lose its reaction if it does. Otherwise, it must go around the jack. Calvary and vehicles must go around a jack.

Options

If you’d like to customize this trap, choose from the options below.

Barbed Wire (Jacks Only): This requires two or more hedgehogs arranged in a contiguous line and no more than 10 feet apart. Strands of metal barbed wire have been strung and secured between them. This creates difficult terrain. A creature that enters this area must make a DC 13 Dexterity saving throw or be caught on the wire and restrained. It takes 1 point of piercing damage each round it remains restrained. It is allowed a new saving throw every round to free itself until it succeeds. It then decides which side of the wire it wants to emerge from.

Barbed Wire has 5 hit points per 5 foot section. It can only be cut by a magic slashing weapon or nonmagical metal snippers. It can be melted by acid (magical or nonmagical).

Bleeder (Spears/Pikes/Stakes Only): The wounds caused by the blades or stakes continue to bleed. On each round after the initial injury occurred, the wounded creature continues to lose 1 hit point per round until it or another creature spend an action to bind the wound(s) caused by the trap. Magic healing also ends this effect. While bleeding, the wounded creature leaves a trail of blood behind it that grants advantage to all rolls made to track it.

Diseased Spears (Spears/Pikes/Stakes Only): The blades or stakes have not been cleaned of the gore from their previous victims. A creature hit by the hedgehog must make a DC 11 Constitution saving throw or be infected with sewer plague.

Electric Wire (Barbed or Razor Wire Only): This wire has been enchanted to deal 1d6 lightning damage per round and create the paralyzed condition in any creature that comes in contact with it. This is in addition to its regular damage and effects. Wet creatures and those in metal armor save with disadvantage. A creature is allowed a new saving throw every round to negate the condition, but this is on top of any other saving throw imposed by the wire. A creature that comes into contact with a paralyzed creature must save vs. the electric wire as if it had touched the wire itself.

Electric Wire has 10 hit points per 5 foot section.

It can only be cut by a magic slashing weapon or nonmagical metal snippers. It can be melted by acid (magical or nonmagical). It radiates evocation magic.

Casting dispel magic on it disarms the electric wire and destroys its enchantment. However, this does nothing to negate its barbed or razor wire properties.

Poison Spears (Spears/Pikes/Stakes Only): The blades or stakes have been recently poisoned. They deal an extra 2d6 poison damage; a successful DC 13 Constitution saving throw reduces the damage by half. The GM is free to use a different poison if desired.

Razor Wire (Jacks Only): This requires two or more hedgehogs arranged in a contiguous line and no more than 10 feet apart. Strands of metal razor wire have been strung and secured between them. This creates difficult terrain. A creature that enters this area must make a DC 15 Dexterity saving throw or be caught on the wire and restrained. It takes 1 point of slashing damage each round it remains restrained. It is allowed a new saving throw every round to free itself until it succeeds. It then decides which side of the wire it wants to emerge from.

Razor Wire has 5 hit points per 5 foot section. It can only be cut by a magic slashing weapon or nonmagical metal snippers. It can be melted by acid (magical or nonmagical).

Rusty Spears (Spears/Pikes/Stakes Only): The blades or stakes are rusty and deal an extra 1d6 necrotic damage. A successful DC 13 Constitution saving throw reduces the damage by half. This effect can also be applied to Barbed or Razor Wire.

Construction Time: Constructing this trap usually takes about a day if using existing weapons, or a few days to a week if harvesting and sharpening wooden stakes. Forging a metal “jack” takes 1 week. Depending on the hedgehog’s design, it may require an engineer, blacksmith, weaponsmith, and/or woodworker.

Cost: 15 gp for a hedgehog made of spears, 35 go for one made of pikes (longer reach), or 5 gp for wooden stakes (same reach as spears). A “jack” costs 50 gp.

Barbed wire costs 5 gp per 5 feet. Razor wire costs 10 gp per 5 feet. Both have minimum orders of 100 feet.

Electric Wire costs 1,000 gp per 10 feet, with a minimum order of 100 feet (10,000 gp).

---

Magic Landmine

A landmine is a magical “booby trap” buried in the ground that occupies a single 5 or 10 foot square.

Radiates: The trap radiates the school of magic for its spell type (usually evocation).

Spot: A DC 15 Perception check in bright light spots it, or DC 17 in dim light, or DC 19 in nonmagical darkness.

Trigger: It is triggered by a Small or larger creature that steps on it. Tiny or incorporeal creatures don’t trigger it.

Effect: The landmine is basically the same thing as a glyph of warding but inscribed on a flat metal disk concealed under dirt and/or foliage. It delivers the spell effects programmed into it, then self-destructs.

Moat

Source Game Master’s Guide to Traps & Terrors

Difficult Terrain

This terrain is a ditch filled with water (or other liquid) surrounding a castle, city, noble estate, or other strategic location. The water may be free-standing and stagnant, perhaps polluted or diseased by sewage, or it may be fresh and fed by a nearby river. The moat serves as an obstacle to discourage intruders from entering the location it defends. Some moats contain dangerous creatures (crocodiles, quippers, etc.), while others are filled with oil or sharpened stakes. Other moats may contain liquids worse than water, such as acid, lava, quicksand, or slime.

Related Traps: Ditch, Drawbridge, Pit (Flooded), Quicksand, Quickslime.

Trigger: This terrain is triggered when a creature enters the moat.

Spot: The moat does not require a check to spot, and the type of liquid it contains should (under most circumstances) be obvious. However, determining whether the moat contains hazards below the surface (such as creatures, stakes, etc.) requires a successful DC 15 Perception check, or DC 17 if the water is murky (which most moats are).

Disarm: N/A, unless the moat can be safely drained or evaporated.

Dimensions:The average moat is 20 feet deep and 20 feet wide, and surrounds the entirety of the location it was built to protect.

Number of Uses: Limitless, until drained.

Reset: N/A

Effect: The moat forces most intruders to swim across it, exposing them to whatever hazards it contains, and making them targets for defenders on the far side, particularly those manning walls or towers.

Creatures using ranged or spell attacks on those in the moat do so with advantage when that attack is made from a wall, tower, or other elevated position. If they are merely across the moat and no more than 10 feet higher than moat-level, then they gain a +1 bonus to their ranged and spell attack rolls instead.

Options

If you’d like to customize this trap, choose from the options below.

Boiling Acid: The moat uses boiling acid to deal an extra 2d6 acid damage per round to any creature exposed to it; a successful DC 13 Dexterity saving throw reduces the acid damage by half. In addition, the area is lightly obscured due to steam.

Boiling Water: The moat uses boiling water to deal an extra 2d6 fire damage per round to any creature exposed to it; a successful DC 13 Dexterity saving throw reduces the fire damage by half. In addition, the area is heavily obscured due to steam.

Choked With Weeds or Debris: The moat is difficult terrain that makes it hard to swim. Any swimming creature must make a successful DC 13 Strength saving throw each round or it becomes restrained. It is allowed a new saving throw every round until it succeeds in freeing itself.

Dirty Water: The water in the trap is contaminated, such as with raw sewage, parasites, and/or decomposing bodies. A creature who falls in or otherwise comes into contact with the water must make a DC 11 Constitution or Dexterity saving throw (whichever score is higher) or be poisoned for a number of hours equal to 10 – its CON modifier (if positive). If the GM wishes, the water can also be diseased.

Paralyzing Slime: The moat is filled with paralyzing slime instead of water. A creature attempting to enter, move through, or escape the coated area at the start of its turn must make a DC 14 Constitution saving throw or be paralyzed for 1 minute. If it fails, it is also knocked prone by a sudden wave of nausea causing it to slip in the slime. Creatures in heavy armor save against this with advantage. A paralyzed creature can make a new save each round to negate the condition.

Paralyzed prone creatures will drown in the slime.

Poison Moat: The moat is filled with poison to deal an extra 2d6 poison damage per round to any creature exposed to it; a successful DC 13 Dexterity saving throw reduces the poison damage by half. In addition, the area is heavily obscured due to steam.

Construction Time: Variable. Assume 1 month for a small estate, fort, or tower, 6 months for a small town or fortress, and 1 year for a city and/or castle. If a river must be diverted to fill the moat, add another month or more, depending on how far away it is.

Cost: Variable. Assume 1,000 go for a small village, fort, or tower, 5,000 gp for a small town or fortress, and 10,000 gp for a city and/or castle. If a river must be diverted to fill the moat, add another 5,000 gp or more, depending on how far away it is.

---

Quicksand

Source Game Master’s Guide to Traps & Terrors

Natural Trap

This is a pool of quicksand that appears to be regular solid or swampy ground until stepped on. It is typically encountered in a jungle or swamp.

Related Traps: Quickslime, Quicklime Geyser.

Trigger: When a creature or object enters the trap.

Spot: Make a DC 15 Perception, Nature, or Survival check to recognize the danger. If you succeed, you may stop before entering. If you fail, make a DC 17 Dexterity saving throw. If you succeed, you catch yourself before falling. If you fail, you fall 5 feet into the quicksand if you walked into it, or 10 feet in if you ran.

Disarm: As natural hazard, quicksand cannot be disarmed or dispelled like a magical or mechanical trap. It can be temporarily frozen solid for 1 hour by 50 points of cold damage.

Dimensions: Any, usually confined to a pool that is 1d3 x 10 feet deep and 1d3 x 10 feet wide.

Number of Uses: Limitless.

Reset: N/A

Effect: Once you fall in, your speed is reduced to 5; however, any panicked, flailing movement causes you to sink deeper, resulting in your speed being reduced by -1 for each round you move in this way. If you remain calm and choose to float in place or slowly make you way to shore, you may do so (subject to any speed penalties above).

Quicksand counts as difficult terrain. Aberrations and oozes move at half-speed inside this terrain, rather than 5 feet.

Options

To customize this trap, choose from the options below.

Buried Treasure: Any sunken objects are left unharmed (except those subject to water damage).

Sympathetic Magic: All Earth and Water magic cast within 30 feet of quicksand has its DC increased by +1 and deals an extra 1d4 psychic damage (from the fear of being trapped and drowning) regardless of whether the spell normally deals psychic damage.

Construction Time: N/A

Cost: N/A

---

Quickslime

Source Game Master’s Guide to Traps & Terrors

Natural Trap

This is a pool of quicksand mixed with flesh-eating acid-slime. Like quicksand, until you step on it, it appears to be solid ground. Unlike real quicksand that can be easily floated on or escaped from, quickslime has a deadly suction effect that causes any movement (not just from panicked, volatile flailing) to make trapped creatures sink deeper.

Related Traps: Quicksand, Quicklime Geyser.

Trigger: When a creature or object enters the trap.

Spot: Make a DC 15 Perception, Nature, or Survival check to recognize the danger. If you succeed, you may stop before entering. If you fail, make a DC 17 Dexterity save. If you succeed, you catch yourself before falling. If you fail, you fall 5 feet into the quickslime if you walked into it, or 10 feet in if you ran.

Disarm: As natural hazard, quickslime cannot be disarmed or dispelled like a magical or mechanical trap. However, it is flammable and can be bubbled away and destroyed if dealt 50 points of fire damage in a single round. It can also be temporarily frozen solid for 1 hour by 50 points of cold damage.

Dimensions: Any, usually confined to a pool that is 1d3 x 10 feet deep and 1d3 x 10 feet wide.

Number of Uses: Limitless until destroyed.

Reset: N/A

Effect: Once you fall in, your speed is reduced to 5; however, any movement causes you to sink deeper, resulting in your speed being reduced by -1 for each round you move.

Quickslime counts as difficult terrain. It deals 1d6 points of acid damage per round to non-aberrations and non-oozes that fall into it. For every round you spend moving in it, you must succeed at a DC 10 Dexterity saving throw or else you accidentally get some quickslime into your eyes. If you do, you are permanently blinded until magically healed Quickslime counts as difficult terrain. Aberrations and oozes are immune to these ongoing damage and blinding effects, but move at half-speed inside this terrain.

Options

To customize this trap, choose from the options below.

Buried Treasure: Any sunken objects are left unharmed (except those subject to water damage).

Sympathetic Magic: All Acid, Earth, and Water magic cast within 30 feet of quickslime has its DC increased by +1 and deals an extra 1d4 acid damage on a failed save regardless of whether it normally deals acid damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: N/A

Cost: N/A

Note: Quickslime first appeared in slightly different form in Extreme Encounters: Weather & Terrain: Acid. You can also find Acid collected in our Unearthly Omnibus.

---

Quickslime Geyser

Source Game Master’s Guide to Traps & Terrors

Natural Trap

This is a 30 x 30 foot puckered hole in a cavern floor or wall, perhaps disguised inside the mouth of an idol of a god or fiend. It smells foul, acrid, and may be mistaken for a pit.

Related Traps: Quicklime Geyser, Steam Geyser.

Trigger: The geyser erupts once every 1d4 hours on its own, or the GM can trigger it early, perhaps via a pressure plate.

Spot: Make a DC 13 Perception, Nature, or Survival check to recognize the danger. If you succeed, you recognize it is a geyser and detect the telltale rumble of an eruption (assuming one is pending). You have 1d3 rounds to get 60+ feet away to safety.

Disarm: As natural hazard, quickslime cannot be disarmed or dispelled like a magical or mechanical trap. However, it is flammable and can be bubbled away and destroyed if dealt 50 points of fire damage in a single round. It can also be temporarily frozen solid for 1 hour by 50 points of cold damage. Dealing this cold or fire damage does not prevent future eruptions, only the current one.

Dimensions: Any, usually confined to a single geyser in the floor of a cave or concealed inside the mouth of a bas-relief in a floor or wall.

Number of Uses: Limitless, until destroyed.

Reset: Automatic (see Trigger).

Effect: Activation of the trap requires all creatures present to roll initiative. The trap rolls initiative with a +8 bonus. If you fail to flee in time, the quickslime geyser erupts for the next 1d4 minutes. During this eruption, it sprays everything in a 60 foot long, 30 foot wide cone with boiling quickslime. Creature and objects caught in the blast suffer 8d6 acid damage every round that they remain in the cone.

Quickslime counts as difficult terrain. Aberrations and oozes are immune to these ongoing damage and blinding effects, but move at half-speed inside this terrain.

Options

To customize this trap, choose from the options below.

Buried Treasure: Any objects buried under quick-slime are left unharmed (except those subject to water damage).

Sympathetic Magic: All Acid, Earth, and Water magic cast within 30 feet of quickslime has its DC increased by +1 and deals an extra 1d4 acid damage on a failed save regardless of whether it normally deals acid damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: This trap takes 4 weeks to build for new construction or double that for existing construction. A substantial source of quickslime must exist on the property or be imported in at great cost and danger (tripling the time and cost). An engineer and stonemason are required.

Cost: 5,000 gp.

Note this trap first appeared in slightly different form in Extreme Encounters: Weather & Terrain: Acid. That book has been collected in our Unearthly Omnibus.

---

Rockslide

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This outdoor trap releases a rockslide down a hill or mountain. It may be used to seal the entrance to a cave (see Cave-In), but its primary purpose is to sweep intruders away from an incline or bury them; its secondary purpose is to create difficult terrain.

Related Traps: Boulder Drop, Cave-In, Collapsing Roof, Crushing Walls, Log Jam.

Trigger: There are two ways this trap may be triggered:

1. Manually by one or more creatures above the rockslide who are aware of the trap or perhaps set it up themselves; or 2. Automatically via a tripwire.

   Spot: The tripwire is 3 inches off the ground. A successful DC 10 Perception check reveals the trip-wire in bright light, while DC 13 spots it in dim light.

DC 15 spots a tripwire in nonmagical darkness or concealed below murky water. If there is no tripwire, and the trap is triggered manually, there may be no way to detect its presence before the trap is activated—this is especially true if the rockslide is coming from a great height and/or recessed area (such as a rocky ledge or shelf) that creatures below could not logically see. If the creatures activating the trap above can potentially be seen, the GM may allow a DC 15 Perception check to spot furtive movement 1 round before the trap is triggered.

Disarm: A successful DC 15 Dexterity saving throw using thieves’ tools breaks the tripwire harmlessly. A character without thieves’ tools can attempt this check with disadvantage using any edged weapon or edged tool. On a failed check, the trap triggers.

Dimensions: A 30-foot-wide cone of dirt, rock, and rubble that quickly descends down the side of the hill or mountain for 300 feet.

Number of Uses: One.

Reset: N/A

Effect: Activation of the trap requires all creatures present to roll initiative. The trap rolls initiative with a +8 bonus. On its turn, the rockslide moves 60 feet in a straight line. The rockslide can move through creatures’ spaces, and creatures can move through its space, treating it as difficult terrain.

Whenever the sphere enters a creature’s space or a creature enters its space while it’s sliding, that creature must succeed on a DC 15 Dexterity saving throw or take 25 (5d10) bludgeoning damage and be knocked prone, restrained (buried alive), and stunned until the end of its next turn. It also suffers 1 level of exhaustion. If the save is failed by 5 or more, the creature is also shoved 20 feet straight back by the rockslide, which, rather than burying them alive, may be enough to knock them off the hill or mountain with appropriate falling damage. If the saving throw is successful, the creature takes half damage and is knocked prone, but is not restrained or stunned. A creature that was buried alive can make a DC 17 Strength saving throw to free itself from the debris.

It can make a new saving throw each round for as many rounds as it has a Strength modifier (minimum of 1). If these saves fail, it must be rescued by another unburied creature that uses its action to free it. A creature that requires air to breathe that remains buried for 2 minutes or more suffocates to death.

The rockslide stops when it hits a wall or similar barrier. It can’t move around corners.

Areas covered by a rockslide become difficult terrain.

Construction Time: Constructing this trap usually takes 1 day for giants, or 1 week for barbarians, dwarves, gnomes, hobgoblins, orcs, rangers, or tribal warriors. Most other creatures require 2 weeks.

Cost: Potentially free from found material, or 50-100 gp if paying for the labor and/or expertise. Like most things, it depends on local market conditions, how fast you need it done, etc. Recruiting humanoids or tribesmen may not be a matter of coin, but of complex barter for supplies or services they need more than coin.

---

Rolling Sphere

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap releases a smooth stone sphere from behind a trapdoor in a high wall or ceiling. The sphere is designed to roll easily, chasing intruders down a corridor and sealing off an area when it stops.

Related Traps: Boulder Drop, Cave-In, Collapsing Roof, Crushing Walls, Log Jam, Rockslide.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap.

Spot: With a successful DC 15 Perception check, a character can spot the trapdoor and pressure plate. A search of the floor accompanied by a successful DC 15 Investigation check reveals variations in the mortar and stone that betray the pressure plate’s presence.

The same check made while inspecting the ceiling notes variations in the stonework that reveal the trapdoor.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

Dimensions: A 10-foot-diameter sphere of stone.

Number of Uses: One, unless reset.

Reset: Generally not possible, but would be relatively easy for a giant. Assume a giant could reset the trap in 30-60 minutes, with a Large giant at the high end and Huge giant at the low end (assuming it can fit and still have reasonable room to work).

Effect: A hidden trapdoor in the ceiling opens, releasing a 10-foot-diameter rolling sphere of smooth, solid stone. Activation of the sphere requires all creatures present to roll initiative. The trap rolls initiative with a +8 bonus.

On its turn, the sphere moves 60 feet in a straight line. The sphere can move through creatures’ spaces, and creatures can move through its space, treating it as difficult terrain. Whenever the sphere enters a creature’s space or a creature enters its space while it’s rolling, that creature must succeed on a DC 15 Dexterity saving throw or take 55 (10d10) bludgeoning damage and be knocked prone. If the save fails by 5 or more, the creature is also stunned until the end of its next turn and suffers 1 level of exhaustion.

The sphere stops when it hits a wall or similar barrier. It can’t go around corners, but smart dungeon builders incorporate gentle, curving turns into nearby passages that allow the sphere to keep moving for the maximum possible distance (and damage to intruders).

Assuming intruders run from the sphere, it makes sense for that path to herd them into a dead end or another trap, (such as a Pit) where the sphere can plug their escape. This can be done by forming a perfect seal, or simply by blocking the way back.

As an action, a creature within 5 feet of the sphere can attempt to slow it down with a DC 20 Strength check. On a successful check, the sphere’s speed is reduced by 15 feet. If the sphere’s speed drops to 0, it stops moving and is no longer a threat.

Options

To customize this trap, choose from the options below.

Bolt Holes: There may be one or more alcoves, gaps, holes, pits, or branching passages in the corridor for creatures to take refuge in from the rolling sphere. A successful DC 15 Perception check reveals one just in time for a fleeing creature to take refuge. These holes may be empty or contain corpses, creatures, or traps.

Odd Color or Composition: The sphere can be made of any hard, durable substance capable of being polished smooth and sustaining hard impacts, such as certain gemstones, crystals, or minerals. The sphere could be magically or naturally colored. It could also be covered with an illusion to look like something else, like a giant incorporeal ball of screaming lost souls…

Construction Time: Constructing this trap requires careful work with its pulley system, as well as building the support structure which holds up the boulder. In addition, the sphere must be properly sized, smoothed, and tested. The corridor or room must also be sized (or resized) to accommodate the boulder’s path, possibly incorporating smooth, curving edges to assist the sphere’s movement. This takes 8 weeks for new construction or 16 weeks to retrofit existing construction (if it is possible at all). A team of skilled engineers and stonemasons is required.

Cost: 25,000 gp for the trap along with up to 120 feet of gentle, curving stone passage for it to roll through.

---

Sinkhole

Source Game Master’s Guide to Traps & Terrors

Natural Trap

This trap is any sloping terrain composed of soft earth or sand, usually dotted with scrub brush. Coastal sand dunes are a prime example. The terrain is notoriously unstable and subject to collapse if subjected to even moderate stress (excluding normal creature movement and combat).

Related Traps: Chute, Crumbling Ledge, Pit (Hidden).

Before You Spring This Trap: Until it collapses, this terrain offers advantages and disadvantages for fighting on it, with the bonus or penalty depending on whether you fighting up- or down-slope, and how steeply the slope is angled.

Both before and after it collapses, the slope/sinkhole counts as difficult terrain.

Fighting On a Slope: If you are descending a slope that angles slightly down (or defending it against creatures trying to come up it), you gain a +1 bonus to attack and creatures below you suffer a -1 penalty to their attack. A slight slope angles up to become a 5 foot elevation at its top. If you are descending a slope that angles strongly down (or are defending it against creatures trying to come up it), you gain a +2 bonus to attack and creatures below you suffer a -2 penalty to their attack. A steep slope angles up to become a 10 foot elevation (or higher) at its top.

Trigger: Any time an area effect attack or spell that deals bludgeoning, fire, force, lightning, or thunder damage is cast into, over, or around the slope, there is a 50% chance it collapses and transforms itself into a sinkhole. This includes falling or grappling creatures landing or wrestling on the slope. You may use percentile dice for this check, or roll a d20, with a result of 1-10 indicating the slope collapses.

Spot: This terrain looks safe to casual observers, but requires a successful DC 15 Investigation check to reveal just how potentially unstable it is. Creatures proficient in Nature or Survival reduce this DC to 13.

Disarm: N/A

Dimensions: One or more slopes of soft earth or sand, typically arranged in 20-60 foot wide spheres.

Number of Uses: One.

Reset: N/A

Effect: Any creatures on the slope at the time it collapses must succeed at a DC 17 Dexterity saving throw or fall from their current slope height into the newly opened sinkhole and be knocked prone. You take half-damage from the fall due to the softer landing the dirt or sand provides. If the save succeeds, you do not fall and are now in the nearest unoccupied square adjacent to the edge of the sinkhole. If you take damage from any source while adjacent to the sinkhole, you must succeed at a DC 8 + the damage dealt Dexterity saving throw or fall and be knocked prone into the sinkhole exactly as if you had failed your save when it was first created.

A creature caught in the bottom of the sinkhole must make 3 consecutive DC 13 Dexterity saving throws in order to escape. Any failure sends it tumbling back to the bottom to start over (there is no fall damage or knocked prone penalty for this).

Options

To customize this trap, choose from the options below.

Creature: While most sinkholes are caused by natural forces, some could be caused by a creature with a burrowing speed such as an ankheg or bulette. The sinkhole could reveal the creature’s tunnel or lair, or the creature could be waiting below to collapse the slope and eat any creatures that fall in.

In this case, the creature could choose to collapse the slope at any time. It will generally wait until its Tremor Sense detects as many creatures as possible have entered the sinkhole’s area of effect. The trap could spring sooner through the actions of the creatures above, or the creature can automatically spring the trap on its turn (roll its Initiative in secret).

Construction Time: N/A

Cost: N/A

---

Spiral Staircase (Difficult Terrain)

This terrain consists of a steep spiral staircase that grants advantages to defenders and disadvantages to attackers. It is usually narrow (5 foot wide) and frequently combined with other traps, either on the spiral staircase itself or at or near the top or bottom.

Related Traps: Ankle Biter, Chute, False Staircase, Illusory Floor, Missing Staircase, Portcullis.

Trigger: The defense is triggered when any creature uses the staircase.

Spot: No check required; it is obviously a staircase.

Disarm: N/A

Dimensions: The entire length and width of the staircase.

Number of Uses: Limitless, unless destroyed/sealed.

Reset: N/A

Effect: The entire staircase counts as difficult terrain. The amount of bright and dim light shed from any source is halved on the stairs due to its steep angle and corners, combined with the narrow width. In addition, the Dash action cannot be taken on this staircase.

For every 60 feet walked up the stairs, a corporeal creature that require air to breathe must succeed at a DC 11 Constitution saving throw. If it fails, it takes 1 level of exhaustion from the climb. Creatures descending the stairs do not suffer exhaustion. Any creature descending the staircase gains advantage on its melee and ranged attack rolls and a +2 bonus to its armor class. Any creature ascending the staircase suffers disadvantage on melee and ranged attack rolls and loses any shield bonus to its armor class.

Only Tiny to Medium weapons may be used when going in either direction; there is no room to swing, shoot, or thrust Large weapons. Spellcasting on the stairs is unaffected for good or for ill.

Options

To customize this trap, choose from the options below.

Landing: This spiral staircase has a small 5-10 foot ledge or landing every 30 feet or so. This offers a place to rest on the climb, as well as a way to allow allies to pass. The landing may or may not connect to another floor. The landing removes the bonuses and penalties for fighting on a spiral staircase while you remain on it.

No Inner Wall: With this optional effect, there is no inner wall or handrail guarding the staircase (or a large portion of it between floors). This dangerous design is most often seen in towers, lighthouses, and similar structures. It accomplishes two things:

1. It gives more room to use a shield when ascending the stairs and restores the AC bonus from using a shield; and 2. It opens the possibility of ascending or descending creatures falling off the stairs—essentially turning the stairs into an open Pit (Simple), with appropriate fall damage. Any creature that takes a critical hit on the stairs must succeed at a DC 8 + damage dealt Dexterity saving throw or fall off them.

Construction Time: It takes a week per 10-foot section to excavate and fashion a stone staircase, plus an additional week if the steps are to be finished properly and made to match the aesthetics of other staircases in the facility. For wooden stairs, this time is halved. Stone staircases require an engineer and stonemason; wooden staircases require an engineer and woodworker.

Cost: 50 gp per 10-foot long, 5-foot wide section of stone staircase, or double that cost to make it 10-foot wide. All costs for a wooden staircase are halved unless expensive wood is used.

---

Statue of Poison Darts

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap consists of four spring-loaded dart launchers concealed in the hand of a Medium, Large, or Huge metal, stone, or wooden statue. The firing hand (not necessarily the entire arm) is pointed down, but its other hand may be in any position, such as holding an object, raised in salute, or clutched over its heart.

Related Traps: Statue Temple, Statue Trap, Wall of Poison Darts.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 15 Perception check reveals the trigger itself (as a discolored floor stone). It requires a DC 20 Investigation check to find the dart launchers concealed in the statue’s fingers.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

This trap can also be disarmed by removing the statue’s arms, or by stuffing the holes in the fingertips with cloth or wax. Make a DC 13 Intelligence check after stuffing the holes to make sure all holes are stuffed and stuffed properly; if failed, the trap still fires 1d2 darts when triggered.

Dimensions: The trap does not take up any extra room, and the darts have enough momentum to strike from one wall to another. The trap is divided into four sections (all activated by the same pressure plate), with each section staggered 5-10 feet apart (or more). This is designed to have the best chance to hit any creatures attempting to run forward or backward once the first volley of the trap activates.

Number of Uses: One, until manually reset.

Reset: The trap must be manually reset. This requires 5 minutes and requires reloading it with darts. The trap is designed to fit any standard-sized dart.

Effect: The statue’s firing arm snaps up to point straight ahead to fire four spring-loaded darts. Each dart makes a ranged attack with a +8 bonus against a random target within 10 feet of the pressure plate (vision is irrelevant to this attack roll). (If there are no targets in the area, the darts don’t hit anything.) A target that is hit takes 2 (1d4) piercing damage per dart and must succeed on a DC 15 Constitution saving throw, taking 11 (2d10) poison damage on a failed save, or half as much damage on a successful one. The GM may substitute another type of poison instead, and/or the poisoned condition.

Options

To customize this trap, choose from the options below.

Diseased: The darts have been smeared with bacteria, fecal matter, or diseased fluids/remains. Any creature that takes damage from it must make a DC 11 Constitution saving throw (per dart) or contract sewer plague. Optionally, you can choose a different disease from the DMG or another book, such as those listed in our Game Master’s Guide to Traits & Actions for Monsters & NPCs. These include brain swell, cackling cough, pus popper, sinister sneeze, vomit plague, and watery bowels. Other possibilities include magical diseases like lycanthropy or vampirism.

Explosive Darts: The darts are packed with an incendiary device that causes them to deal an extra 1d4 fire damage (per dart). A successful DC 15 Dexterity saving throw reduces the damage by half.

Flammable objects hit by these darts that are not worn or carried by a creature catch fire.

---

Steam Geyser

Source Game Master’s Guide to Traps & Terrors

Natural Trap

This is a 30 x 30 foot puckered hole in a cavern floor or wall, perhaps disguised inside the mouth of an idol of a god or fiend. Warm mist and hazy plumes of gray-white steam emanate from it.

Related Traps: Lightning Web, Quicklime Geyser.

Trigger: The geyser erupts once every 1d4 hours on its own, or the GM can trigger it early, perhaps via a pressure plate.

Spot: Make a DC 13 Perception, Nature, or Survival check to recognize the danger. If you succeed, you recognize it is a geyser and detect the telltale rumble of an eruption (assuming one is pending). You have 1d3 rounds to get 60+ feet away to safety.

Disarm: As natural hazard, the geyser cannot be disarmed or dispelled like a magical or mechanical trap. However, it is liquid and can be frozen solid if dealt 50 points of cold damage. Dealing this cold damage does not prevent future eruptions, only the current one.

Dimensions: Any, usually outdoors or confined to a single geyser in the floor of a cave, or concealed inside the mouth of a bas-relief statue face in a floor or wall.

Number of Uses: Limitless ,until destroyed.

Reset: Automatic (see Trigger).

Before You Spring This Trap: Pre-eruption, anything left within 60 feet of the geyser for more than 1 minute becomes damp, and anything left within 30 feet of it becomes wet in 3 rounds.

Effect: Activation of the trap requires all creatures present to roll initiative. The trap rolls initiative with a +8 bonus. If you fail to flee in time, the steam geyser erupts for the next 1d4 minutes. It sprays everything in a 60 foot long, 30 foot wide cone with boiling steam. Creatures and objects caught in the cone suffer 8d6 fire damage every round they remain in it and are blinded until the end of their next turn if they fail a DC 15 Dexterity saving throw. Note that unlike regular fire, water offers no protection against the fire damage from heat and steam.

A 60 foot cylinder around the geyser becomes heavily obscured by steam, and an additional 60 feet becomes lightly obscured. This obscurement remains for the duration of the eruption and for 2d6 minutes afterward. Anything within 120 feet of the geyser during this time becomes damp, and anything within 60 feet of it becomes wet. Damp creatures save at -1 against lightning damage and effects, while wet creatures save with disadvantage against lightning damage or effects (such as shocking grasp). Anything dropped on the ground is swiftly obscured by the steam; it requires a DC 10 Perception check to find lightly obscured ones and DC 12 for heavily obscured ones. Any ground-based traps (such as pressure plates or tripwires) impose disadvantage to spot them.

Options

To customize this trap, choose from the options below.

Summon Water Elemental: When the geyser erupts a water elemental is summoned from out of its depths. It may or may not be hostile to any creatures present, and departs as the eruption ends. Optionally, the geyser could be a gate to the Elemental Plane of Water (but only while it is actively erupting).

Sympathetic Magic: All Fire and Water magic cast within 30 feet of the geyser has its DC increased by +1 and deals an extra 1d4 fire damage on a failed save regardless of whether it normally deals fire damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: This trap takes 4 weeks to build for new construction or double that for existing construction. A substantial source of steam must exist on the property. An engineer and stonemason are required.

Cost: 4,000 gp.

---

Swinging Death

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap is designed to swing a large, heavy spiked wooden object such as a log or battering ram down at an angle onto an unsuspecting victim’s chest (if Medium size) or head (if Small).

Related Traps: Man-Trap.

Trigger: The trap is triggered by any Small or larger creature that touches the tripwire, which is a thin wire strung from one side of the area to the other. Tiny or incorporeal creatures do not activate the trap.

Spot: The tripwire is 3 inches off the ground. A successful DC 10 Perception check reveals the tripwire in bright light, while DC 13 spots it in dim light. DC 15 spots a tripwire in nonmagical darkness or concealed below murky water. If the trap is concealed by foliage, the DC is increased by +2. If the GM wishes, evidence of past trap strikes against adjacent trees or walls may be visible, reducing the DC by -2.

Disarm: A successful DC 15 Dexterity saving throw using thieves’ tools breaks the tripwire harmlessly. A character without thieves’ tools can attempt this check with disadvantage using any edged weapon or edged tool. On a failed check, the trap triggers.

Dimensions: The trap is a Large log or battering ram (optionally studded with iron spikes). The log is attached to a tree or ceiling by ropes or chains. If indoors, the hole in the ceiling is large enough to easily accommodate the swinging object while still allowing it to move freely and quickly in an arc down into its target’s space. The hidden room that houses the trap must be able to contain both this object and any other machinery necessary for its activation, such as pulleys or weights.

Number of Uses: One, until manually reset.

Reset: A 13 or higher Strength score is required to reset the trap. Resetting it takes 10 minutes for a single creature or half that time for a team of two or more working together.

Effect: Once triggered, the log or battering ram swings down at high speed. It remains attached to its ropes or chains so it can be more easily reset. Any creature or object in its path that fails a DC 17 Dexterity saving throw takes 4d8 bludgeoning damage (plus an extra 3d6 piercing damage if it is spiked). In addition, the creature hit is knocked prone, takes 1 level of exhaustion, and is stunned until the end of its next turn. If the save is successful, the creature dodges out of the way and takes no damage (if it has room to move, which it may not if the trap is indoors).

A Medium creature that chooses to drop prone rather than dodge reduces its saving throw DC to 15, and a Small creature that does the same reduces its DC to 13. If the creature that triggered the trap successfully saves, the log or ram continues on to strike any adjacent Small or larger creature in the next 2 squares directly behind it. Afterward, the log or ram slowly swings to a standstill and can be easily avoided. However, it still occupies the top and middle portion of a single 5-foot square (or 10-foot square if the GM prefers), which becomes difficult terrain. To move through its space, Medium creatures must crawl under it, and Small creatures must duck. Tiny creatures can move freely through its space. Large creatures must go around it.

Huge or Gargantuan creatures can step over it (assuming they have room).

Options

If you’d like to customize this trap, choose from the options below.

Bleeder: The wounds caused by the trap continue to bleed. On each round after the initial injury occurred, the wounded creature continues to lose 1 hit point per round until it or another creature spend an action to bind the wound(s) caused by the trap. Magic healing also ends this effect. While bleeding, the wounded creature leaves a trail of blood behind it that grants advantage to all rolls made to track it.

Diseased Spikes: The spikes have not been cleaned of the gore from previous victims or have been smeared with feces. A creature hit by them must make a DC 11 Constitution saving throw or be infected with sewer plague.

Poison Spikes: The spikes have been recently coated with poison. This deals an extra 4d6 poison damage; a successful DC 13 Constitution saving throw reduces the damage by half. The GM is free to use a different poison.

Rusty Spikes: The spikes are rusty and deal an extra 1d6 necrotic damage. A successful DC 13 Constitution saving throw reduces the damage by half.

Construction Time: Constructing this trap usually takes a day for barbarians, fey, hobgoblins, orcs, rangers, or tribal warriors in the woods, or double that for most others. For indoor use, it takes a week for new construction or double that for existing construction.

Cost: Potentially free from found material for wilderness use, or up to 25 gp if paying for the individual components, labor, and/or expertise. For indoor use, the cost rises to 50 gp for new construction or 100 gp for existing construction.

---

Wall of Acid

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap releases a wall of acid within 60 feet of its trigger.

Related Traps: Acid Cauldron, Quickslime, Quickslime Geyser.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 15 Perception check reveals a discolored floor stone (the pressure plate) and/or the acid-proof jets in the area the acid appears from.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered. See also Reset, below.

Dimensions: The wall appears as a vertical barrier.

The wall can be up to 60 feet long, 20 feet high, and 1 foot thick, or a ringed wall up to 20 feet in diameter, 20 feet high, and 1 foot thick. The wall is opaque.

Number of Uses: One, until reset.

Reset: The trap automatically resets itself after ending the wall. It recycles most of the acid from the wall, so it can be used an unlimited number of times, though the GM may wish to impose a limit on maximum uses based on the available acid supply (located somewhere nearby in a secret room).

Resetting or disarming the trap requires 1 minute for a creature with less than a 13 Strength score to pull the stubborn lever up, or half that time for a creature with greater Strength.

Effect: When the wall appears, each creature within its area must make a DC 17 Dexterity saving throw.

On a failed save, a creature takes 20 (5d8) acid damage and is blinded for 1 minute, or it takes half as much damage on a successful save and is not blinded. Each turn, a blinded creature can make a new saving throw to negate the condition. Both sides of the wall deal 20 (5d8) acid damage to each creature that ends its turn within 10 feet of that side or inside the wall. A creature takes the same damage when it enters the wall for the first time on a turn or ends its turn there. The wall lasts for 1 minute or until the trap is disarmed.

Options

To customize this trap, choose from the options below.

Stinking Cloud: Due to toxic fumes from the acid, the wall gives off the nonmagical equivalent of a stinking cloud spell centered on itself. This cloud dissipates 1d10 minutes after the trap is disarmed. It cannot be blown away while the wall is in operation because the acid just keeps replacing the fumes with more fumes.

Sympathetic Magic: All Acid, Poison, and Water magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 acid damage on a failed save regardless of whether it normally deals acid damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap usually takes about 4 weeks for new construction or double that to retrofit existing construction. It requires an engineer and stonemason.

Cost: 4,000 gp.

---

Wall of Broken Glass (Difficult Terrain)

This terrain consists of broken glass mortared into the top of a wall to deter intruders. Clear, green, and brown are the most common colors. Broken glass is prevalent as a cheap security measure in urban slums, but can also be found surrounding a wealthy citizen’s estate or important facility. Rarely, the outside wall will also be covered in broken glass as a further deterrent to anyone climbing or coming near. Inward-facing walls are almost never covered in broken glass for the safety of those living or working inside.

Related Traps: Ditch, Hedgehog, Moat.

Trigger: When any creature attempts to climb up and/or over the wall, or falls or is knocked prone on it, it encounters broken glass.

Spot: It requires a successful DC 10 Perception check to see the glass and recognize the danger. Due to the reflective nature of the glass, the DC increases by +2 in dim light or nonmagical darkness and decreases by +2 in bright light.

Disarm: Broken glass cannot be disarmed. It can be made less dangerous by smashing it one shard at a time, but this is both noisy and time-consuming.

Assuming someone bothers to do this, it takes 1 minute to reduce the damage in a 5-foot section by half but cannot eliminate the damage completely.

Dimensions: One or more connecting walls around a property.

Number of Uses: Limitless, unless destroyed.

Reset: That section of wall must be repaired and/or re-mortared with new broken glass added. This takes 1 hour per 10-foot section of wall, and a further 24 hours for the mortar to set.

Effect: Creatures move at half-speed in this terrain even if they are immune to slashing damage, as the glass creates an uneven platform of difficult terrain. In addition, any creature touching the broken glass (such as attempting to climb up or over it) takes 1d4 slashing damage. A creature that falls, jumps, or becomes prone on broken glass takes 1d4 piercing damage +2 points of slashing damage. Creatures in heavy armor take half damage from this terrain.

Options

To customize this trap, choose from the options below.

Bleeder: The wounds caused by this trap continue to bleed. On each round after the initial injury occurred, the wounded creature continues to lose 1 hit point per round until it or another creature spends an action to bind the wound(s) caused by the trap. Magic healing also ends this effect. While bleeding, the wounded creature leaves a trail of blood behind it that grants advantage to all rolls made to track it.

Construction Time: 1 hour per 10-foot section of wall to be covered, and a further 24 hours for the mortar to set; this does not include the time to build the wall.

Cost: 10 gp per 10 foot section of wall to be covered in broken glass; this does not include the cost to build the wall.

---

Wall of Fire

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap forms a wall of fire from hidden jets in the floor. The wall appears within 60 feet of its trigger.

Related Traps: Fire Walk, Lava Doom.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 15 Perception check reveals a discolored floor stone (the pressure plate) and/or the jets in the area the wall appears from. These jets could be in the walls, ceiling, or floor, or all three.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered. See also Reset, below.

Dimensions: The wall appears as a vertical barrier.

The wall can be up to 60 feet long, 20 feet high, and 1 foot thick, or a ringed wall up to 20 feet in diameter, 20 feet high, and 1 foot thick. The wall is opaque.

Sniffing the jets reveals a foul, sulfurous odor, but the odor cannot be detected more than a foot above each jet.

Number of Uses: One, until reset.

Reset: The trap automatically resets itself after extinguishing the wall. It can be used an unlimited number of times, though the GM may wish to impose a limit on maximum uses based on the available fuel supply (located somewhere nearby in a secret room).

Manually resetting or disarming the trap requires 1 minute for a creature with less than a 13 Strength score to pull the stubborn lever up, or half that time for a creature with greater Strength.

Effect: When the wall appears, each creature within its area must make a DC 17 Dexterity saving throw.

On a failed save, a creature takes 20 (5d8) fire damage, or half as much damage on a successful save.

Both sides of the wall deal 20 (5d8) fire damage to each creature that ends its turn within 10 feet of that side or inside the wall. A creature takes the same damage when it enters the wall for the first time on a turn or ends its turn there. The wall lasts for 1 minute or until the trap is disarmed.

Fire Light: The wall sheds bright fiery light in a 20 foot radius and dim fiery light for an additional 20 feet.

Options

To customize this trap, choose from the options below.

Colored Flame: The flames are a non-standard color of the trap-maker’s choice. This is a purely cosmetic.

Smoke: The trap emits the nonmagical equivalent of a fog cloud spell centered on itself, except it is oily black smoke. Any creature within 20 feet of the smoke cloud must succeed on a DC 13 Constitution saving throw or be poisoned (by smoke inhalation) until it leaves the heavily obscured area and for 1 round thereafter.

The area becomes heavily obscured in a 20 foot radius and lightly obscured for an additional 20 feet. Anything dropped on the ground is swiftly obscured by the smoke; it requires a DC 10 Perception check to find them if lightly obscured or DC 12 if heavily obscured. Any ground-based traps (such as pressure plates or tripwires) impose disadvantage to spot them.

Sympathetic Magic: All Fire and Cloud magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 fire damage on a failed save regardless of whether it normally deals fire damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap usually takes about 4 weeks for new construction or double that to retrofit existing construction. It requires an engineer and stonemason.

Cost: 4,000 gp.

---

Wall of Hands (Creature Trap)

Source Game Master’s Guide to Traps & Terrors

This trap appears as a standard tomb wall covering both sides of a narrow stone passage that is only 5-feet wide. The walls each feature a large number of symmetrical Tiny holes placed at random heights and covered by cobwebs. The narrow confines of the passage force Small or larger creatures who enter it to walk single file and at half their normal speed.

Related Traps: Wall of Snakes.

Trigger: The trap is activated when a living creature enters the mid-point of the passage.

Spot: A successful DC 15 Perception check reveals dark shadowy movement in one or more of the holes.

Disarm: This trap can only be disarmed by a cleric using Turn Undead; this causes the hands to retreat inside the wall for 1 hour. If Destroy Undead is used instead, treat the hands as CR 3 mummies. Constructs and undead do not trigger this trap and are never targeted by it.

Dimensions: This trap has an area of effect covering both walls of a 30-foot section of narrow, 5-foot wide passage.

Number of Uses: Limitless, as long as the hands are not destroyed, either by damage or Destroy Undead.

Reset: The trap must be restocked with new undead hands.

Effect: Activation of the trap requires all creatures present to roll initiative. The trap rolls initiative with a +8 bonus. Once a living creature reaches the mid-point of the passage it (and any others that are present) are attacked by the severed hands of mummified undead that live in the walls. Each hand extends from its hole on either side of the wall to claw at the living. This grants it advantage on its first attack roll.

Assume there are two severed hands for every living creature in the passage, and each attacks and deals damage with the rotting fist action of a mummy.

The hands have 13 hit points each but otherwise share the stat block of a mummy. The hands relentlessly attack until no living creatures are in range.

Options

To customize this trap, choose from the options below.

Breakaway Walls: If any spells are cast that deal force, lightning, or thunder damage near or to the walls, you can have the walls shatter and mummies emerge to attack instead of just their severed hands! In this case, assume the hands were attached to actual mummies. Scale the number of mummies to the party’s CR (or use your best judgment). If you make too many mummies and a TPK (Total Party Kill) looks inevitable, simply reduce their hit points or have them crumble to dust on the next hit.

Pickman’s Model: You can replace the mummies with ghasts or ghouls for their paralyzing touch.

Sympathetic Magic: All Necromancy magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 necrotic damage on a failed save regardless of whether it normally deals necrotic damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: 4 weeks to prepare the mummies and construct the trap. It requires a stonemason and an arcane or divine caster with access to a spell or ritual that creates mummies.

Cost: 500 gp for the trap plus 500 gp per mummy.

---

Wall of Liquid Poison

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

The trap releases a wall of liquid poison within 60 feet of its trigger.

Related Traps: Poison Needle, Wall of Paralyzing Poison, Wall of Petrifying Poison Gas.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 15 Perception check reveals a discolored floor stone (the pressure plate) and/or the jets in the area the poison appears from.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered. See also Reset, below.

Dimensions: The wall appears as a vertical barrier.

The wall can be up to 60 feet long, 20 feet high, and 1 foot thick, or a ringed wall up to 20 feet in diameter, 20 feet high, and 1 foot thick. The wall is opaque.

Number of Uses: One, until reset.

Reset: The trap automatically resets itself after ending the wall. It recycles most of the poison from the wall, so it can be used a near-unlimited number of times, though the GM may wish to impose a limit on maximum uses based on the available poison supply (located somewhere nearby in a secret room that requires a DC 17 Investigation check to find). Also, recycled poison may become less potent over time, so feel free to reduce the save DC by -2 if the trap has not had its poison “freshened up” in the past month.

Manually resetting or disarming the trap requires 1 minute for a creature with less than a 13 Strength score to pull the stubborn lever up, or half that time for a creature with greater Strength.

Effect: When the wall appears, each creature within its area must make a DC 17 Dexterity saving throw. On a failed save, a creature takes 20 (5d8) poison damage and is poisoned for 1 minute, or half as much damage on a successful save and is not poisoned. Each turn, a poisoned creature can make a new saving throw to negate the condition.

Both sides of the wall deal 20 (5d8) poison damage to each creature that ends its turn within 10 feet of that side or inside the wall. A creature takes the same damage when it enters the wall for the first time on a turn or ends its turn there. The wall lasts for 1 minute or until the trap is disarmed.

Options

To customize this trap, choose from the options below.

Empowered Poison: The powerful poison in this trap bypasses poison resistance and deals half damage to creatures with poison immunity.

Sympathetic Magic: All Poison and Water magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 poison damage on a failed save regardless of whether it normally deals poison damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap usually takes about 4 weeks for new construction or double that to retrofit existing construction. It requires an engineer and stonemason.

Cost: 2,500 gp.

---

Wall of Paralyzing Poison

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

The trap releases a wall of paralyzing poison mist within 60 feet of its trigger.

Related Traps: Poison Needle, Wall of Liquid Poison, Wall of Petrifying Poison Gas.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 15 Perception check reveals a discolored floor stone (the pressure plate) and/or the jets in the area the poison appears from.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered. See also Reset, below.

Dimensions: The wall appears as a vertical barrier.

The wall can be up to 60 feet long, 20 feet high, and 1 foot thick, or a ringed wall up to 20 feet in diameter, 20 feet high, and 1 foot thick. The wall is opaque.

Number of Uses: One, until reset.

Reset: The trap automatically resets itself after ending the wall. It recycles most of the poison from the wall, so it can be used an unlimited number of times, though the GM may wish to impose a limit on maximum uses based on the available poison supply (located somewhere nearby in a secret room, with a successful DC 17 Investigation check required to find it). Manually resetting or disarming the trap requires 1 minute for a creature with less than a 13 Strength score to pull the stubborn lever up, or half that time for a creature with greater Strength.

Also, recycled poison may become less potent over time, so feel free to reduce the saving throw DC by -2 if the trap has not had its poison “freshened up” in the past month.

Effect: When the wall appears, each creature within its area must make a DC 17 Dexterity saving throw.

On a failed save, a creature takes 20 (5d8) poison damage and is paralyzed for 1 minute, or half as much damage on a successful save and is not paralyzed. Each turn, a paralyzed creature can make a new saving throw to negate the condition.

Both sides of the wall deal 20 (5d8) poison damage to each creature that ends its turn within 10 feet of that side or inside the wall. A creature takes the same damage when it enters the wall for the first time on a turn or ends its turn there. The wall lasts for 1 minute or until the trap is disarmed.

Options

To customize this trap, choose from the options below.

Lingering Paralysis: A creature that recovers from being paralyzed by this trap still suffers lingering muscle spasms for 1 minute. During this recovery period, the creature’s attack rolls, saving throws, and skills checks are made with disadvantage.

Sympathetic Magic: All Cloud, Poison, and Water magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 poison damage on a failed save regardless of whether it normally deals poison damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap usually takes about 4 weeks for new construction or double that to retrofit existing construction. It requires an engineer and stonemason.

Cost: 3,000 gp.

---

Wall of Petrifying Poison Gas

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

The trap releases a wall of petrifying poison gas within 60 feet of its trigger.

Related Traps: Poison Needle, Wall of Liquid Poison, Wall of Paralyzing Poison.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 15 Perception check reveals a discolored floor stone (the pressure plate) and/or the jets in the area the gas appears from.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered. See Reset.

Dimensions: The wall appears as a vertical barrier.

The wall can be up to 60 feet long, 20 feet high, and 1 foot thick, or a ringed wall up to 20 feet in diameter, 20 feet high, and 1 foot thick. The wall is opaque.

Number of Uses: One, until reset.

Reset: The trap automatically resets itself after ending the wall. It runs off a limited gas supply, so the GM may wish to impose a limit on maximum uses based on the available supply (located somewhere nearby in a secret room; a successful DC 17 Investigation check finds it). Manually resetting or disarming the trap requires 1 minute for a creature with less than a 13 Strength score to pull the stubborn lever up, or half that time for a creature with greater Strength.

Effect: When the wall appears, each creature within its area must make a DC 17 Dexterity saving throw.

On a failed save, a creature takes 20 (5d8) poison damage and is petrified for 24 hours, or half as much damage on a successful save and is not petrified.

Each turn, a petrified creature can make a new saving throw to negate the condition.

Both sides of the wall deal 20 (5d8) poison damage to each creature that ends its turn within 10 feet of that side or inside the wall. A creature takes the same damage when it enters the wall for the first time on a turn or ends its turn there. The wall lasts for 1 minute or until the trap is disarmed.

Options

To customize this trap, choose from the options below.

Sudden Statue Syndrome: A creature that recovers from being petrified by this trap still suffers lingering muscle spasms until it finishes a long rest. Until then, the creature’s attack rolls, saving throws, and skills checks are made with disadvantage.

Sympathetic Magic: All Cloud and Poison magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 poison damage on a failed save regardless of whether it normally deals poison damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap usually takes about 4 weeks for new construction or double that to retrofit existing construction. It requires an engineer and stonemason.

Cost: 6,000 gp.

---

Wall of Poison Darts

Mechanical trap

When a creature steps on a hidden pressure plate, poison-tipped darts shoot from spring-loaded or pressurized tubes cleverly embedded in the surrounding walls. An area might include multiple pressure plates, each one rigged to its own set of darts.

Related Traps: Poison Needle, Statue of Poison Darts, Wall of Liquid Poison, Wall of Paralyzing Poison, Wall of Petrifying Poison Gas.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap.

Spot: The tiny holes in the walls are obscured by dust and cobwebs, or cleverly hidden amid bas-reliefs, murals, or frescoes that adorn the walls. A successful DC 15 Perception check spots the holes. With a successful DC 15 Investigation check, a character can deduce the presence of the pressure plate from variations in the mortar and stone used to create it, compared to the surrounding floor.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

Stuffing the holes with cloth or wax prevents the darts contained within from launching. Make a DC 13 Intelligence check after stuffing the holes to make sure all holes are stuffed and stuffed properly; if failed, the trap still fires 1d2 darts when triggered.

Dimensions: One wall.

Number of Uses: One or many (GM’s choice how many darts are loaded).

Reset: A single creature can reload the trap full of darts in 10 minutes, or a team of two or more in half that time.

Effect: When triggered, the trap releases four darts.

Each dart makes a ranged attack with a +8 bonus against a random target within 10 feet of the pressure plate (vision is irrelevant to this attack roll). (If there are no targets in the area, the darts don’t hit anything.) A target that is hit takes 2 (1d4) piercing damage and must succeed on a DC 15 Constitution saving throw, taking 11 (2d10) poison damage on a failed save, or half as much damage on a successful one. The GM is free to swap in a different poison if desired (paralysis, sleep, etc.).

Options

To customize this trap, choose from the options below.

Diseased: The darts have been smeared with bacteria, fecal matter, or diseased fluids/remains. Any creature that takes damage from it must make a DC 11 Constitution saving throw (per dart) or contract sewer plague. Optionally, you can choose a different disease from the DMG or another book, such as those listed in our Game Master’s Guide to Traits & Actions for Monsters & NPCs. These include brain swell, cackling cough, pus popper, sinister sneeze, vomit plague, and watery bowels. Other possibilities include magical diseases like lycanthropy or vampirism.

Explosive Darts: The darts are packed with an incendiary device that causes them to deal an extra 1d4 fire damage (per dart). A successful DC 15 Dexterity saving throw reduces the damage by half.

Flammable objects hit by these darts that are not worn or carried by a creature catch fire.

Some walls might be positioned not to fire at the creature that triggered them, but instead at large flammable objects to start a conflagration or explosion.

This could be done to dispose of evidence, distract the authorities, and/or to help the villains escape by putting a wall of fire between them and the party.

Rusty Darts: The darts are rusty and deal an extra 1d4 necrotic damage (per dart). A successful DC 11 Constitution saving throw reduces the damage by half.

Construction Time: This trap requires 4 weeks to construct for new construction or double that for existing construction. This includes the time to create the artistic bas-relief, mural, or fresco to conceal it. It requires an engineer, stonemason, and an artist (for the mural or fresco) or sculptor (for bas-relief).

Cost: 2,000 gp, plus the cost o1f the poison.

---

Wall of Snakes (Creature Trap)

Source Game Master’s Guide to Traps & Terrors

This trap appears as a standard uneven cave wall covering both sides of a passage. The walls each feature a large number of asymmetrical Medium-size holes placed at random heights. The holes do not appear to be man- or machine-made, but could be the result of burrowing creatures.

Related Traps: Wall of Hands.

Trigger: The trap is activated when a living creature enters the mid-point of the passage.

Spot: A successful DC 15 Perception check reveals dark shadowy movement in one or more of the holes.

Disarm: This trap cannot be disarmed because it is not so much a trap as a nest of creatures that must be killed or driven away to “deactivate” it. Filling the holes with smoke, fire, water, or other dangerous or irritating substances will drive the snakes out of their nest onto the passage floor, where they attack any creatures present.

Dimensions: This trap has an area of effect covering both walls of a 30-foot section of passage.

Number of Uses: Limitless, while the snakes live.

Reset: New snakes must be inserted to take up residence in the trap to reset it if the old ones die.

Effect: Activation of the trap requires all creatures present to roll initiative. The trap rolls initiative with a +8 bonus. A creature that reaches the mid-point of the passage is attacked by a giant poisonous snake that lives in the walls. It darts its head out to bite, then retracts back inside the hole it sprang from.

This grants it advantage on its attacks and disadvantage on attacks by creatures against it that require a roll to hit. After the snake attacks, a second giant poisonous snake attacks a random creature behind the one that triggered the trap. It too has advantage on its attack and attacks against it are made with disadvantage. Any creature in the passage that moves forward is attacked by a third giant poisonous snake. It too has advantage on its attack and attacks against it are made with disadvantage.

The snakes do not attack creatures that do not move unless they have no other target. If a snake loses half its hit points, it retreats back into its nest out of reach until it heals or smaller, less dangerous prey approaches.

Options

To customize this trap, choose from the options below.

Tentacles or Animated Vines: Another option is to replace the snakes with tentacles or vines that are part of some larger unseen aberration or plant monster to really scare the players! Simply give them the same stats as the snakes but add the Constrict trait from a giant constrictor snake. Also look at the Reel trait of the roper.

Tougher Snakes: The GM is free to scale this trap by increasing the snakes’ hit points, armor class, attack bonus, and/or bite and poison damage.

Underwater: You can place this trap in fresh water and keep the snakes (turn them into giant water moccasins or similar swimming snakes). Or, you can place the trap in salt water (perhaps in a coral reef) and use giant moray eels instead of snakes.

Sympathetic Magic: All Poison magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 poison damage on a failed save regardless of whether it normally deals poison damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: N/A

Cost: N/A (unless purchasing the creatures)

---

Giant Moray Eel

This Large eel lives in reefs and sea caves. Use stats for plesiosaurus except it only breathes water. It gains Blindsight 60 feet. Any creature that comes within 30 feet of its lair will cause it to shoot halfway out and attack, hoping to score a quick, easy meal. It retracts back into its lair if it hits (along with its victim), or if it loses half its HP.

Bite: +6 to hit, reach 20 feet, one target. Hit: 3d6+4 piercing damage and creature hit is restrained (speed 0) until the eel loses half its hit points or is slain.

The eel will thrash a victim that doesn’t die from its bite. Thrash: Automatic 1d6+2 piercing damage to the bite victim each round until the eel releases you or it is slain. The eel will always thrash a struggling, restrained creature in its jaws unless damaged by other creatures.

---

Wall of Spears

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap appears as a standard stone wall with no visible sign of danger. When triggered by stepping on a pressure plate, four spears spring out to strike at the creature who triggered the trap. The spears are mounted at head, chest, abdomen, and upper leg level (assuming it was designed to strike a Medium-size creature of average height).

Related Traps: Ankle Biter, Ballista Corridor, False Door, Wall of Spikes, Antlers, or Bone.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 15 Perception check reveals a discolored floor stone (the pressure plate) and/or subtle apertures in the stone wall around the trap’s four spear outlets.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

Dimensions: This trap has an area of effect covering a one-foot space stretching from wall to wall, effectively sealing off the passageway except for creatures crawling under or through the spears.

Number of Uses: One, until manually reset.

Reset: The trap must be manually reset by someone who can open two secret panels on either side of each spear outlet on both walls. These can be found and accessed by succeeding on a DC 15 Perception check.

Resetting the trap requires 5 minutes for a creature with less than a 13 Strength score to retract and secure each spear back into its original position, or half that time for someone with greater Strength.

Effect: The creature that stepped on the pressure plate must make a successful DC 17 Dexterity saving throw or take 4d8 piercing damage from all four spears slamming outwards from their outlets simultaneously. On a failure, it is impaled, takes 2 levels of exhaustion, is stunned until the end of its next turn, and restrained until freed by another creature (or if it can teleport itself out). A creature that succeeds on its saving throw takes no damage but is pushed backward or forward 5 feet in its attempt to get out of the way (creature’s choice which direction it moves).

The trap’s four spring-loaded spears are crafted from solid steel and tipped with barbed edges; they shoot out from both sides of the passageway (2 from the left wall and 2 from the right). This fills up the space directly in front of them. These spears create difficult terrain to pass through them.

The safest way past the spears is to crawl under or through them; this uses all of the creature’s movement that round and it loses its reaction.

Options

To customize this trap, choose from the options below.

Bleeder: The wounds caused by this trap continue to bleed. On each round after the initial injury occurred, the wounded creature continues to lose 1 hit point per round until it or another creature spends an action to bind the wound(s) caused by the trap. Magic healing also ends this effect. While bleeding, the wounded creature leaves a trail of blood behind it that grants advantage to all rolls made to track it.

Diseased Spears: The spearheads have not been cleaned of the gore from previous victims. A creature hit by them must make a DC 11 Constitution saving throw or be infected with sewer plague.

Frozen Spears: The spears have been enchanted to deal an extra 2d6 cold damage; a successful DC 13 Constitution saving throw reduces the damage by half. The spears remain cold for 2 rounds after the initial strike, dealing an extra 1d6 cold damage and 1 level of exhaustion per round to any creature that touches them (such as the impaled creature and anyone trying to free it). After this, the spears lose their magic and are safe to touch.

Lightning Spears: The spears have been enchanted to deal an extra 2d6 lightning damage; a successful DC 13 Constitution saving throw reduces the damage by half. Wet creatures or those in metal armor save with disadvantage. The spears remain electrified after the initial strike, dealing an extra 1d6 lightning damage to any creature that touches them (such as the impaled creature and anyone trying to free it). This damage continues for 1d4+1 rounds, then the spears lose their magic and are safe to touch.

Poison Spears: The spearheads have been recently coated with poison. This deals an extra 2d6 poison damage; a successful DC 13 Constitution saving throw reduces the damage by half. The GM is free to use a different poison (paralysis, sleep, etc.).

Rusty Spears: The spearheads are rusty and deal an extra 2d6 necrotic damage. A successful DC 13 Constitution saving throw reduces the damage by half.

Construction Time: Constructing this trap usually takes about 2 weeks for new construction or double that to retrofit existing construction. It requires an engineer, and possibly an arcane or divine caster if using one of the enchanted options.

Cost: 500 gp for standard spear options. Poison is extra. The frozen or lightning options require an arcane or divine caster to cast cone of cold or lightning bolt (depending on damage type desired) on the spears once a day, every day for 2 weeks before they become enchanted.

---

Wall of Spikes, Antlers, or Bone

Source Game Master’s Guide to Traps & Terrors

Difficult Terrain

This terrain consists of a iron spikes or antlers mortared into the top of a wall to deter intruders. Like broken glass, spikes or antlers are prevalent as a wall-top security measure, but are more likely to be found surrounding a wealthy citizen’s estate or important facility than in urban slums. These defenses are considered “classier” and more durable than broken glass. Bones are rarely seen except guarding temples of the dead or necromancer lairs.

Rarely, the outside wall will also be covered in spikes, antlers, or bones as a further deterrent to anyone climbing or coming near. Inward-facing walls are almost never covered in them for the safety of those living or working inside.

You can also use this terrain for a spiked iron gate or fence, such as those seen around cemeteries or merchant or noble estates.

Sometimes, spikes, antlers, or bones may be attached to a freestanding wood wall, then dragged into position to add to the fall damage at the bottom of a Pit Trap or Missing Staircase.

Related Traps: Ditch, Moat, Wall of Broken Glass.

Trigger: When any creature attempts to climb up and/or over the wall, or falls or is knocked prone on it, it encounters the spikes or antlers.

Spot: It requires a successful DC 10 Perception check to see the spikes or antlers and recognize the danger. The DC increases by +1 in dim light or +2 in nonmagical darkness.

Disarm: Spikes, antlers, or bones cannot be disarmed. Unlike broken glass, these defenses cannot be substantially removed by smashing them.

Dimensions: One or more connecting walls around a property.

Number of Uses: Limitless unless destroyed.

Reset: That section of wall must be repaired and/or re-mortared with new spikes, antlers, or bones added. This takes 1 hour per 10-foot section of wall, and a further 24 hours for the mortar to set.

Effect: Creatures move at half-speed in this terrain even if they are immune to piercing damage, as the spikes or antlers create a platform of difficult terrain.

In addition, any creature that falls, jumps, or is knocked prone onto the spikes, antlers, or bones takes 1d6+2 piercing damage. Creatures in heavy armor take half damage from this terrain.

Options

To customize this trap, choose from the options below.

Bleeder: The wounds caused by this trap continue to bleed. On each round after the initial injury occurred, the wounded creature continues to lose 1 hit point per round until it or another creature spends an action to bind the wound(s) caused by the trap. Magic healing also ends this effect. While bleeding, the wounded creature leaves a trail of blood behind it that grants advantage to all rolls made to track it.

Sympathetic Magic: All Necromancy magic cast within 30 feet of a wall of antlers or bone has its DC increased by +1 and deals an extra 1d4 necrotic damage on a failed save regardless of whether it normally deals necrotic damage or not. The trap itself does not benefit from this bonus unless the GM wishes it. (A wall of spikes has no sympathetic magic bonus.)

Construction Time: 1 hour per 10-foot section of wall to be covered, and a further 24 hours for the mortar to set; this does not include the time to build the wall.

Cost: 20 gp per 10 foot section of wall to be covered in spikes or antlers; this does not include the cost to build the wall.

Secret Panels & Rooms

If not otherwise indicated in a trap’s description, any secret trap control wall panels or rooms mentioned can always be found with a successful DC 17 Investigation check. Just add it to your dungeon even though it’s not on the map you’re using. Who’s gonna know?

---

Wall of Stone

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap consists of a wall of stone that slides into place (either up, down, or side to side), sealing intruders in (or out) of an area. It is located in a stone archway, ceiling, doorway, or wall.

Related Traps: Cave-In, Collapsing Roof, Crushing Walls, Rockslide, Rolling Sphere.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 15 Perception check reveals a discolored floor stone (the pressure plate) and/or subtle apertures in the area the wall slides out from.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered. See also Reset, below.

Dimensions: The wall is 6-inches thick and is composed of one 10-foot-by-10-foot panel that is contiguous with at least one other ceiling, floor, or wall. In some cases, the wall is 20-feet long, but still 10-feet thick.

Number of Uses: One, until reset.

Reset: The trap must be manually reset via a lever hidden inside a secret control panel nearby (and outside the sealed area. This panel can be found and accessed with a successful DC 15 Investigation check. Resetting or disarming the trap requires 1 minute for a creature with less than a 13 Strength score to pull the stubborn lever up, or half that time for a creature with greater Strength.

Effect: When triggered, a stone wall slides into place to seal off the area with a loud grinding sound that can be heard for 500 feet. The effect is similar to a nonmagical version of wall of stone. If the wall cuts through a creature’s space when it appears, the creature is pushed to one side of the wall (its choice).

The wall is the same general shape, look, and texture as the rest of the walls in the area. It can’t occupy the same space as a creature or object. The wall is vertical and rests on a firm foundation. It merges with and is solidly supported by existing stone.

The wall is an object made of stone that can be damaged and thus breached. The wall has AC 15 and 30 hit points per inch of thickness. Reducing it to 0 hit points destroys it. In rare cases, this might cause connected walls to collapse at the GM’s discretion (see related traps like Cave-In or Collapsing Roof for ideas).

The wall is permanent and can’t be dispelled.

Construction Time: Constructing this trap usually takes about 4 weeks for new construction or double that to retrofit existing construction. It requires an engineer and stonemason.

Cost: 2,000 gp.

COPYRIGHT NOTICE Open Game License v 1.0a Copyright 2000, Wizards of the Coast, LLC.

System Reference Document 5.1 Copyright 2016, Wizards of the Coast, Inc.; Authors Mike Mearls, Jeremy Crawford, Chris Perkins, Rodney Thompson, Peter Lee, James Wyatt, Robert J. Schwalb, Bruce R. Cordell, Chris Sims, and Steve Townshend, based on original material by E. Gary Gygax and Dave Arneson.

All other content Copyright 2023 by MageGate Games Inc. Author: Jackson Dean Chase.

Index / Exhaustion Rules Exhaustion Rules

The deadliest traps in this book make use of exhaustion rules. We strongly recommend you use our optional rules instead of the official 5e ones!

Our rules more or less affect all classes equally, instead of unfairly penalizing skill-heavy classes like rogues upfront and no one else. Our rules use the same 6 level structure, so that makes it easy to use them in your game!

Exhaustion Table

Level 1: -1 to ability checks, attack rolls, damage rolls, and saving throws, -1 to the DC of any spells or spell-like abilities you cast.

Level 2: -2 to ability checks, attack rolls, damage rolls, and saving throws, -2 to the DC of any spells or spell-like abilities you cast.

Level 3: Disadvantage and -3 on ability checks, attack rolls, damage rolls, and saving throws, -3 to the DC of any spells or spell-like abilities you cast, speed reduced to half.

Level 4: Disadvantage and -4 to ability checks, attack rolls, damage rolls, and saving throws, -4 to the DC of any spells or spell-like abilities you cast, speed reduced to 10 feet.

Level 5: Disadvantage and -5 on ability checks, attack rolls, damage rolls, and saving throws, -5 to the DC of any spells or spell-like abilities you cast, speed reduced to 5 feet.

Level 6: Incapacitated until your wounds are tended to by another and/or you complete a long rest. (The official rules kill you instead!)

~~~ MAGIC TRAPS ~~~ Alcove of Illusion

Source Game Master’s Guide to Traps & Terrors

Magic Trap

This trap creates an illusion over any creature that enters its alcove and teleports it to a predetermined location. The trap may consist of one or multiple alcoves.

Related Traps: Cursed Shrine, Illusory Floor.

Radiates: Conjuration and illusion magic.

Trigger: The trap is triggered when a living creature enters its alcove.

Spot: The trap is disguised behind intricate runes etched into the stone floor in and around its entryway. A successful DC 15 Perception check is required to spot it. There may be other cryptic clues as to what the trap does, such as this inscription: Become what you hate to gain what you love.

Disarm: The trap can be disarmed by casting dispel magic upon it or by defacing/destroying the runes. The runes have 10 hit points and are vulnerable to acid, bludgeoning, force, lightning, and thunder damage.

They are resistant to piercing and slashing damage, and immune to cold, fire, necrotic, poison, psychic, and radiant damage.

Dimensions: One stone alcove up to 5 feet wide and tall enough to fit a single Medium-sized creature.

Number of Uses: Limitless.

Reset: The trap resets every day at dusk.

Effect: When a Medium size or smaller creature enters the alcove, the trap does two things to it at the same time:

1. It creates a realistic illusion over it (complete with auditory, olfactory, thermal, and visual, but not tactile components). The illusion appears to change the outward appearance and/or creature type, but not its size beyond a foot or two in either direction. In all other ways, it functions exactly as the seeming spell. It persists until the creature finishes a long rest or has dispel magic cast upon it; and 2. It teleports the creature (now covered by the illusion) to a well-known location of the trapmaker’s choice. This location can be anywhere within 1-100 miles away, but cannot be changed once set.
2. Choose a creature type or roll 1d20 on the table below to determine the illusion granted: Once created, the trap always creates the same type of illusion. In most cases, this will not have been randomly chosen, but be of a creature type related to or revered by the trap-maker. In rare cases, the illusion may take on the exact appearance of the (presumably) long-dead trap-maker. In the hands of a clever owner, this is not so much a trap but a means to carry out nefarious plans at range and in near-perfect disguise.
3. The other main use, of course, is to split intruders up and then trick the main group into attacking the illusion-covered member, thinking it’s a monster or other enemy. Since the illusion also changes the affected character’s voice, it may be hard to convince them of their true identity (especially at range).

Options

If you’d like to customize this trap, choose from the options below.

Sympathetic Magic: All illusion magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 psychic damage on a failed save regardless of whether it normally deals psychic damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap requires extensive knowledge in both engineering and illusion magic as well as having access certain rare ingredients from exotic locales. In addition, it requires casting seeming and teleportation circle 7 times each over 7 days per alcove.

Cost: Building this trap costs 5,000 gp per alcove.

---

Arcane Archway

Source Game Master’s Guide to Traps & Terrors

Magic Trap

This trap takes the form of a stone archway decorated in arcane symbols and valuable gemstones. The archway is shrouded in opaque mist of a color of the trapmaker’s choosing. It is surrounded by a faintly glowing aura that sheds dim light for 30 feet.

Related Traps: Astral Redirect, Teleport Trap.

Radiates: Conjuration and transmutation magic.

Trigger: The trap is triggered when a creature passes through the archway.

Spot: The archway itself requires no roll to spot. A successful DC 10 Arcana or Religion check reveals the presence of strange magical energy radiating from the archway. There may be some cryptic clue as to the trap’s purpose inscribed over the archway, such as, “Fear not, and seek your true path” or “The lonely road reveals the soul.” Disarm: Casting dispel magic disarms the trap for 1 hour. Removing any of the gems initiates a self-destruct sequence. In 3 rounds, the archway explodes in a burst of bludgeoning stone and raw magical force. This deals 9 (3d6) bludgeoning and 9 (3d6) force damage to all creatures and objects in a 30 foot radius. It also violently expels any creatures currently inside the archway, who take the same damage plus an extra 9 (3d6) psychic damage from being ripped from one reality to another.

Dimensions: The arch stands about 8 feet tall and wide.

Number of Uses: Limitless.

Reset: The trap resets every day at midnight.

Effect: When a creature passes through the archway, it is plane shifted to an abandoned section of either the Feywild, the Shadowfell, or one of the Lower Planes.

The destination is preprogrammed by the caster at the time of installation and cannot be changed. The area is hauntingly beautiful, yet lonely and sinister. It is also heavily contaminated with Fey Spores (if in the Feywild), Fiendish Spores (if on the Lower Planes), or Shadow Spores (if in the Shadowfell).

Choose or roll 1d6 on the table below to determine which plane the archway plane shifts you to:

Fey Spores: The trap releases a cloud of spores gathered from the Feywild. The spores spread around corners. Any creature caught in the trap’s area of effect must succeed on a DC 15 Constitution saving throw.

d6	Arcane Archway Destination
1-2	Lower Planes (choose one)
3-4	Feywild
5-6	Shadowfell

If it fails, it takes 4d6+4 psychic damage as it takes on an increasingly fey-like appearance (pointed ears, large eyes, delicate fingers and other physical features) over the next week. Its creature type changes to fey. If the save succeeds, it takes half damage as its body successfully fights off the physical changes. Every midnight after moving more than 1 mile from the trap’s location, a creature who failed its original saving throw is allowed a new one to return to its original form and creature type, but the DC increases by +1 per night. It is allowed one additional save per day equal to its Constitution modifier (minimum of 1). If all those saves fail, the physical changes become permanent.

Fiend Spores: The trap releases a cloud of spores gathered from one or more Lower Planes, but usually all from within layers of the same plane (the Abyss, the Hells, Hades, etc.). The spores spread around corners. Any creature caught in the trap’s area of effect must succeed on a DC 15 Constitution saving throw. If it fails, it takes 4d6+4 psychic damage as it takes on an increasingly tiefling-like appearance (not including wings) over the next week. Its creature type changes to fiend. If the save succeeds, it takes half damage as its body successfully fights off the physical changes. Every midnight after moving more than 1 mile from the trap’s location, a creature who failed its original saving throw is allowed a new one to return to its original form and creature type, but the DC increases by +1 per night. It is allowed one additional save per day equal to its Constitution modifier (minimum of 1). If all those saves fail, the physical changes become permanent.

Shadow Spores: The trap releases a cloud of spores gathered from the Shadowfell. The spores spread around corners. Any creature caught in the trap’s area of effect must succeed on a DC 15 Constitution saving throw. If it fails, it takes 4d6+4 psychic damage as it takes on an increasingly pale, undead-like appearance over the next week. Its creature type changes to undead. If the save succeeds, it takes half damage as its body successfully fights off the physical changes. Every midnight after moving more than 1 mile from the trap’s location, a creature who failed its original saving throw is allowed a new one to return to its original form and creature type, but the DC increases by +1 per night. It is allowed one additional save per day equal to its Constitution modifier (minimum of 1). If all those saves fail, the physical changes become permanent.

Regardless of which plane a creature was shifted to, after the saving throw is made (and regardless of its success or failure), the creature is plane shifted back to emerge from the archway, only to find 24 hours have passed in its world, despite having only been lost on the other plane for 24 minutes. Optionally, if the trap-maker has linked multiple arcane archways together, the creature may emerge through a different archway back into its world if desired (usually within 10-100 miles).

Options

If you’d like to customize this trap, choose from the options below.

Sympathetic Magic: All Conjuration, Transmutation, and Water magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 psychic damage on a failed save regardless of whether it normally deals psychic damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap takes 3 weeks for new construction or double that to retrofit existing construction. An engineer and stone mason are required along with rare gems and an arcane or divine caster to fog cloud and plane shift over the arch and its gems 7 times over 7 days.

Cost: 50,000 gp.

---

Arcane Security System

Source Game Master’s Guide to Traps & Terrors

Magic Trap

This trap installs multiple floating eyes powered by arcane energy at strategic points within a lair. The eyes do not need to be mounted or touching a wall or other terrain. Paranoid wizards and the ruthless organizations that employ them are fond of this trap.

Radiates: Divination and evocation magic.

Trigger: The eyes function as a medieval security camera system, reporting everything they see to the trap-maker and/or authorized creatures. The eyes have Darkvision (120 feet) that see through magical darkness. They can also see invisible and ethereal creatures.

When an unauthorized creature of Tiny size or greater enters scanning range (120 feet), the trap triggers. The trap-maker can designate specific or general types of creatures that do not trigger the trap.

Spot: A successful DC 15 Perception check spots an eye unless it’s concealed (this raises the DC to 17).

Disarm: A successful dispel magic disarms and destroys the eye; optionally, it only disarms it for 1 hour.

Dimensions: The eye is a Tiny construct typically placed at or near the top of the corner of a corridor or room, or along a wall or in the branches of a tree.

Number of Uses: Limitless, until dispelled.

Reset: The trap automatically resets whenever the last target passes out of range.

Effect: Activation of the trap requires all creatures present to roll initiative. The trap rolls initiative with a +8 bonus. Each eye in range briefly glows as it shoots three magic missiles, preferring to concentrate fire on the closest target until that creature passes out of range. For this reason, sometimes multiple eyes with over-lapping scanning ranges will be placed near each other.

Options

If you’d like to customize this trap, choose from the options below.

Sympathetic Magic: All Divination and Force magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 force damage on a failed save regardless of whether it normally deals force damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap takes 4 weeks per eye. It requires an arcane caster to cast alarm, arcane eye, and magic missile 7 times each across 4 weeks over a diamond that is consumed in the casting and becomes the eye. Once placed in position, the eye cannot be moved without it losing its magic.

Cost: 3,000 gp per eye, or 2,000 gp per eye if it can’t cast magic missile. If dispel magic only temporarily disarms the eye, triple its cost. The cost does not include the 1,000 gp diamond.

---

Astral Redirect

Source Game Master’s Guide to Traps & Terrors

Magic Trap

This trap redirects creatures on the Astral Plane to an alternate, predetermined location on another plane (or to an Astral pocket dimension). It is typically created to kidnap unwary mortal astral travelers and press them into service to extraplanar rulers, either as pawns, slaves, servants, or in the best case scenario, as clerics or warlocks.

Related Traps: Arcane Archway, Teleport Trap.

Radiates: Conjuration and illusion magic.

Trigger: The trap is triggered when an astral creature enters its area of effect.

Spot: To spot this trap, a successful DC 17 Arcana or Religion check must be made. When spotted, the trap appears as a slightly wavering transparent bubble that has a chameleon-like ability to blend in with its surroundings.

Disarm: The trap can be disarmed by casting dispel magic on it; this causes the trap to become inactive for a number of hours equal to the Intelligence, Wisdom, or Charisma modifier of the caster (minimum of 1).

Dimensions: The trap has no physical form. It is incorporeal since it exists solely on the Astral Plane; however, its area of effect is a 120-feet diameter sphere.

Number of Uses: Limitless.

Reset: This trap functions once per day and resets every day at midnight. If the GM wishes, time is lengthened on the Astral Plane vs. the Material Plane, so 24 hours to astral creatures is only 24 minutes to creatures on the Material Plane. Once a creature enters a plane other than the Material, the GM is again free to distort time in any direction desired.

Effect: When triggered, a plane shift spell transports any living mortal creature, ghost, or unattached soul within the trap’s area of effect to a predetermined destination on another plane, demiplane, or astral pocket dimension chosen by the trap-maker at the time of construction. The trap cannot distinguish between hostile and friendly targets and will target all living mortal creatures within range equally. Extraplanar creatures (celestials, elementals, fey, and fiends) are considered immortal and immune to the effect, as are corporeal undead. However, incorporeal undead are not immune.

Any objects that are worn or carried by plane shifted creatures are instead shifted to a location of the trapmaker’s choosing set at the time the trap was created.

This location must be somewhere on the plane the trap teleports creatures to (within 100 miles of the point the teleported creatures arrive).

Possible planar destinations (Choose or roll 1d6):

An astral pocket dimension is similar to a demiplane but is much smaller in size (equivalent to a feudal estate, all the way up to a single large city). It is always ruled by a single, often tyrannical entity such as an aberration, demigod, fallen celestial, fiend, ghost, lich, or wizard. If this entity is slain, its pocket dimension rapidly dissolves back into the Astral Plane from which it was formed from. The entity needs to collect living creatures with souls (or simply lost souls) to worship it and this, along with the entity’s iron will, provides the energy that sustains its pocket dimension.

d6	Characteristic
1 Astral Pocket Dimension or Demiplane
2	Alternate Prime Material Plane where everyone and every god the party knows has the opposite alignment
3-4	Elemental Plane (usually Fire, specifically the efreeti-ruled City of Brass)
5-6	Lower Plane (usually one of the Hells)

Options

If you’d like to customize this trap, choose from the options below.

Less Cruel Option: If the GM wishes, each plane-shifted creature can make a DC 17 Charisma saving throw to hang onto a number of items of their choice equal to their Charisma modifier (minimum of 1).

These arrive scattered at random over a 1 mile sphere around the shifted creatures.

More Cruel Option: If the GM wishes, each plane-shifted creature appears at random within 1 mile of the others that shifted with them (and their belongings, if also using the “nice” option).

Sympathetic Magic: All conjuration magic cast within 120 feet of this trap has its DC increased by +1 and deals an extra 1d4 psychic damage on a failed save regardless of whether it normally deals psychic damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this type trap requires extensive knowledge in both engineering and conjuration and illusion magic as well as having access certain rare ingredients from exotic locales. It also requires an astral or extraplanar creature to cast plane shift over the trap’s area every day for a year to make it permanent.

Cost: Building this trap costs 10,000 gp (in research fees and exotic extraplanar components).

Cursed Shrine

Source Game Master’s Guide to Traps & Terrors

Magic Trap

This trap involves a seemingly ordinary, nonmagical shrine to any evil deity, demigod, or warlock patron. It is typically found in an abandoned, overgrown area, inside a cultist’s lair, or as a pilgrimage site. It may be a simple altar and statue in a roadside or wilderness area, or part of a more elaborate (and defensible) building. The GM has a lot of latitude here as to what it looks like, but a shrine is always smaller than a church or temple, with fewer available guards and staff (if tended at all). Many shrines are long abandoned and located in dangerous, desolate, or difficult terrain.

Radiates: Enchantment and necromancy magic.

Related Traps: Alcove of Illusion, Statue Temple.

Trigger: This trap is triggered by a living creature touching the shrine, praying to it, or desecrating it.

Spot: Spotting this trap (but not the shrine itself) requires a successful DC 17 Arcana or Religion check or casting detect magic or detect evil and good. With a successful skill check, the nature of the trap is hinted at by the ancient runes or symbols covering it.

Casting detect evil and good reveals the shrine radiates evil in a 120-foot radius sphere around the building.

Disarm: Disarming this trap requires defacing the runes and/or symbols equivalent to half the shrine’s hit point total, or by casting dispel magic. Defacing the shrine removes the trap. Casting dispel magic deactivates the trap for a number of hours equal to the caster’s spellcasting ability score modifier.

Dimensions: The trap’s area of effect covers a 30-foot radius sphere around the shrine. The shrine itself may be Small to Huge, but always fits within the epicenter of the area of effect.

Number of Uses: Limitless.

Reset: Once triggered, the trap goes dormant for a short rest before resetting itself. During this time, it does not radiate magic or evil, and creatures may be tricked into thinking the trap is no longer active.

Effect: When triggered, all creatures within a 30- foot radius sphere (centered on the shrine) must make a successful DC 15 Wisdom saving throw or have their alignment shift one step closer to evil. In addition, they suffer 1 level of exhaustion. If already evil, the creature’s alignment shifts one step closer to the evil alignment of the deity, demigod, or warlock patron the shrine is dedicated to, and it removes 1 level of exhaustion instead (provided the creature already has at least 1 level of exhaustion at the time the trap is triggered). If an evil creature has no levels of exhaustion to remove, then it gains +10 temporary hit points until it completes a long rest, and these temporary hit points apply to constructs and undead as well as to living creatures.

In addition, each creature that fails its saving throw must also immediately make a DC 13 Wisdom saving throw or become charmed as if affected by a charm person spell with the following additional effects: their alignment changes to match that of their new patron deity (this may temporarily override this trap’s normal alignment shift); they are compelled to perform rituals at any shrine or temple associated with this shrine’s deity, demigod, or warlock patron; and they become devout followers of that deity and do whatever they can to further its goals, even at great personal cost. This charmed condition persists for 24 hours after creatures leave the shrine.

A creature who successfully saves against either effect is immune to this cursed shrine’s effect for 24 hours, but not to a different cursed shrine.

Shrine Hit Points: The shrine has 30 hit points per size category (30-120). It is immune to cold, fire, necrotic, poison, and psychic damage, and resistant to piercing, radiant, and slashing damage. It is vulnerable to acid, bludgeoning, force, lightning, and thunder damage.

Options

If you’d like to customize this trap, choose from the options below.

Arcane Dead Zone: Arcane magic fails (and the spell slot is wasted) when cast in this trap’s area of effect if cast by one not of the shrine’s faith. This is combined with a magic mouth effect that warns, “Your magic cannot save you here!” This effect is divine in origin, cast by deity or demigod. Dispel magic does not remove it and instead deals 5d4 necrotic or radiant damage (trap-maker’s choice, no saving throw) to the caster every time it is cast.

Divine Dead Zone: Divine magic fails (and the spell slot is wasted) when cast in this trap’s area of effect if cast by one not of the shrine’s faith. This is combined with a magic mouth effect that warns, “Your god cannot hear you here!” This effect is arcane or divine in origin, cast by deity, demigod, lich, or warlock patron. Dispel magic does not remove it and instead deals 5d4 force damage (no save) to the caster every time it is cast.

Offerings: The faithful or superstitious left offerings at the shrine, such as bones, teeth, objects, or trinkets.

These rarely have any value beyond a few copper (cp), but may provide a clue or warning to the curious.

Polymorph: The trap casts polymorph on the creature that triggered it. The form is preprogrammed by the trap-maker and cannot be changed. The form is usually of an unhelpful and/or traumatizing nature, and/or thematic to the location or to the religion represented.

Sympathetic Magic: All enchantment and necromancy magic cast within 30 feet of a cursed shrine has its DC increased by +1 and deals an extra 1d4 psychic damage on a failed save regardless of whether it normally deals psychic damage or not. The trap does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap takes 2 weeks per size category. It requires an adept crafts-person, stonemason, sculptor, and/or woodworker utilizing such components as exotic wood, bone, silver, or blessed stones imbued with divine power to activate its effect.

An arcane or divine caster is also required to cast charm person and bestow curse must be cast on the shrine 6 times over 6 nights per size category, always at midnight, and always after completing the ritual sacrifice of a living humanoid, whose blood is smeared over the shrine’s runes and/or symbols. The GM is free to invent other required spells, rituals, or conditions.

Cost: 500 gp per size category.

---

Electrocution Door

Source Game Master’s Guide to Traps & Terrors

Magic Trap

This trap consists of a metal doorknob, ring, or knocker charged with electricity. The doorknob may be set in a wooden or metal door. This trap is favored mainly by storm cults or evocation wizards.

Related Traps: False Door, Guillotine Door, Lightning Web, Wall of Lightning.

Radiates: Evocation magic.

Trigger: The trap activates when the doorknob is touched by any unauthorized creature. Creatures immune to lightning damage do not trigger the trap.

Spot: A successful DC 15 Perception check in bright light spots some odd symbols inscribed on the doorknob, ring, or knocker. The DC increases to DC 17 in dim light or DC 19 in nonmagical darkness.

Once spotted, a successful DC 15 Arcana or Religion check identifies the symbols as pertaining to evocation magic—specifically lightning—and identifies any associated deity, demigod, or warlock patron.

Disarm: Casting dispel magic on the trap removes it.

Dimensions: The size of a standard doorknob, ring, or loop knocker.

Number of Uses: One.

Reset: N/A

Effect: The trap has been enchanted to electrocute any unauthorized creature touching or opening the door. This deals 2d6 lightning damage to it for 1d4+1 rounds (minimum of 2), during which time the target is paralyzed and cannot release their grip on the trap. Any creature touching that creature while it is being electrocuted receives the same damage and is also paralyzed. A successful DC 15 Constitution saving throw reduces the lightning damage by half but does not remove the paralyzed condition.

Wet creatures and/or those wearing metal armor save with disadvantage.

Options

If you’d like to customize this trap, choose from the options below.

Sympathetic Magic: All Lightning and Thunder magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 lightning damage on a failed save regardless of whether it normally deals lightning damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: This trap takes 3 days, assuming an existing doorknob, ring, or knocker is being inscribed. It requires an arcane or divine caster to cast call lightning, lightning bolt, or a similar spell into the trap 3 times over 3 days. It is during this time that the caster programs which creatures are authorized to bypass the trap (this cannot be changed afterward).

Cost: 3,000 gp.

---

Entombed In Ice

Source Game Master’s Guide to Traps & Terrors

Magic Trap

This trap consists of a room or corridor floor made from what appears to be a solid block of ice. The temperature on and within 30 feet of the ice is a constant 20 degrees below freezing. The ice is blue-white and semi-translucent so creatures and objects buried in it are partially visible. However, the floor beneath the ice cannot be seen all the way to its bottom, so the total depth of the ice cannot be determined (and is up to the GM).

Radiates: Evocation and transmutation magic.

Related Traps: Moat, Pit (Flooded), Pit (Simple), Sinkhole, Wall of Ice, Wall of Petrifying Poison Mist.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to the ice. Tiny or incorporeal creatures do not activate the trap, nor do creatures immune to cold damage.

Spot: A successful DC 13 Arcana or Religion check reveals the ice to be magical and possibly dangerous to touch. A successful DC 13 Investigation check reveals the specific creature and/or object type of those trapped 10 feet beneath the ice. A successful DC 15 Investigation check reveals the general creature and/or object type of those trapped 20 feet beneath the ice. The general type of anything trapped deeper than that cannot be determined unless it is Huge or Gargantuan and even then it requires a DC 17 Investigation check.

Disarm: Casting dispel magic (DC 18) on the trap disarms it for 1 minute; this does not remove the ice, only prevents its ability to damage or entomb new creatures or objects.

Dimensions: At minimum, the ice takes up the length and width of the entire floor of the area it appears in. It can be as deep as the GM desires (possibly connecting to another, deeper level), to a minimum depth of 60 feet.

Number of Uses: Limitless, until destroyed.

Reset: The trap remains constantly on.

Effect: When triggered, any creature or object on the ice must make a DC 13 Dexterity saving throw for every 10 feet it travels (in any direction). If it succeeds, it takes 1d6 cold damage. If it fails, it becomes petrified (by freezing solid) and 1 round later, sinks 1d6 x 10 feet beneath the ice, which immediately refreezes over it. It remains in that state until freed by another creature (see Destroy, below).

• The ice floor is considered difficult terrain. A creature that successfully crosses the entire length of the ice by foot suffers 1 level of exhaustion from undergoing the anxiety and bone-chilling cold of the experience. Creatures immune or resistant to cold, or those that flew, teleported, or used other magic to successfully cross, do not suffer this exhaustion.

  DESTRUCTION

  Dealing 60 points of acid, fire, force, lightning, or thunder damage to the ice removes one 10 foot layer (either the entire floor’s worth, or only that section the creature, item, or spell affects).

  This act frees any creatures or objects entombed at that depth, but they take half damage. Creatures or objects below that depth do not take damage. This damage may be repeated, with every 60 points removing another 10 foot layer until the ice is destroyed and the true floor of the room is revealed.

• The trap is immune to bludgeoning, cold, necrotic, piercing, poison, psychic, radiant, and slashing damage.

  Creatures that were petrified (frozen) by the ice have not aged past the time they were entombed, but resume aging normally once freed. The victims of the ice initially appear frost-covered and act as if under the effects of a slow spell until they gradually thaw out over the next 10 minutes. They are blinded, and remain so for a minimum of 1 hour; afterward, they are allowed a DC 15 Constitution saving throw to negate the condition. If that fails, they are allowed a new save every hour until they succeed.

  Options

  To customize this trap, choose from the options below.

  Cursed Ice: This version of the trap’s ice is cursed; any humanoid creature entombed by it must make a DC 11 Constitution saving throw each day it remains entombed or be permanently transformed into an icy, blue-skinned ghast that deals an extra 1d6 cold damage with its claws in addition to the normal slashing damage and paralysis effect.

  Ice Storm (1/Day): Whenever the trap is attacked (see Destroy, above), it casts ice storm centered on the creature responsible for the most damage. This has no effect on creatures or objects trapped beneath the ice.

  Sleet Storm (1/Day): Whenever the trap is attacked (see Destroy), it casts sleet storm centered on the creature responsible for the most damage. This has no effect on creatures or objects trapped beneath the ice.

  Summon Extraplanar Guardians (1/Day): When it is attacked, the trap summons two ice- or cold-related elementals or fiends of CR 3-5, or five of the same creature type of CR 2 or less. The called creatures arrive by a mystic gate within 30 feet of the trap in 1 round and attack all unauthorized creatures present, remaining and/or pursuing them until defeated or destroyed, or until 1 hour passes.

  Sympathetic Magic: All Cold and Necrotic magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 cold damage on a failed save regardless of whether it normally deals cold damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

  Construction Time: Constructing this trap takes 8 weeks for new construction or double that to retrofit existing construction. It requires an engineer and an arcane or divine caster who can cast freezing sphere.

  Cost: 6,000 gp.

  Illusory Floor

Source Game Master’s Guide to Traps & Terrors

Magic Trap

This trap consists of a normal seeming dirt, stone, or wooden floor typical for the type of building it is found in. However, the floor is an illusion covering a chasm, flooded area, pit, etc. In some cases, it is simply the secret entrance to a basement, dungeon, or other area.

Radiates: Illusion magic.

Related Traps: Pit (Hidden).

Trigger: The trap is triggered when a corporeal creature or object of any size interacts with the floor.

Spot: A successful DC 17 Arcana check reveals something is “not quite right” about the floor in a magical sense. It does not reveal it to be an illusion. A second DC 17 Arcana check confirms the floor is an illusion, but does not reveal what it is covering. A gnome or illusionist gains advantage on all Arcana checks to spot and identify this illusion.

Disarm: Casting dispel magic (DC 18) disarms the trap for 1 hour.

Dimensions: All or any portion of the length and width of a room or corridor.

Number of Uses: Limitless.

Reset: See Disarm, above.

Effect: When any creature or object enters the area of floor covered by this illusion, it must succeed at a DC 17 Dexterity saving throw or fall (taking appropriate falling damage). If it was running, the DC is increased to 19. If it stepped just inside the doorway but did not attempt to advance further than one square, the DC is reduced to 15.

View From Below the Trap: Whether or not creatures below the illusory floor see the illusion or through it is up to the GM. If the base is manned, then the view from below should be designed to see through the illusion, since this is more strategic for the defenders.

Construction Time: Constructing this trap takes 1 week for new construction or 2 weeks to retrofit existing construction (assuming an existing floor must be removed). An arcane or divine caster is required to cast hallucinatory terrain over the floor 7 times over 7 days.

Cost: 4,000 gp.

---

Lightning Web

Source Game Master’s Guide to Traps & Terrors

Magic Trap

This trap magically creates a web of interlocking lightning bolts inside an existing corridor, passage, or tunnel. It must be grounded against preexisting walls, floor, and ceiling or the effect fizzles before it can do any damage.

Radiates: Evocation magic.

Related Traps: Electrocution Door, Wall of Lightning

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap, nor do creatures immune to lightning damage.

Spot: A successful DC 15 Perception check reveals a discolored floor stone (the pressure plate).

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

Dimensions: A lightning web can be up to 10 feet wide by 30 feet long.

Number of Uses: One, until reset.

Reset: The trap automatically resets itself after deactivating the lightning web. It can be used an unlimited number of times per day. To disarm or manually reset the trap, a lever hidden inside a secret control panel nearby (and outside the sealed area) must be accessed. This panel can be found and accessed with a successful DC 15 Investigation check. Resetting the trap requires 1 minute for a creature with less than a 13 Strength score to pull the stubborn lever up, or half that time for a creature with greater Strength.

Effect: Any creature of Medium size or smaller that is caught in the web when it goes live, or that attempts to bypass it afterward, must make a DC 15 Dexterity saving throw for every 10 feet it travels through the web (in either direction). It takes 12 (4d6) lightning damage on a failed save and is knocked prone. Wet creatures, or those in metal armor, save with disadvantage. On a successful save, the creature takes no damage, is not knocked prone, and advances 10 feet down the passage. Any creature of Large size cannot bypass the web; it can still move down the passage, but automatically takes the damage. It is not knocked prone.

Huge or Gargantuan creatures cannot fit inside the passage, but automatically take damage (but are not knocked prone) if they attempt to reach inside it.

The lightning web remains active for 10 minutes or until dispelled (whichever comes first).

Options

If you’d like to customize this trap, choose from the options below.

Adrenaline Burnout: A creature paralyzed by this trap suffers 1 level of exhaustion each time it is paralyzed by it.

Sympathetic Magic: All Lightning and Thunder magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 lightning damage on a failed save regardless of whether it normally deals lightning damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap takes 4 weeks for new construction or double that to retrofit existing construction. It requires an engineer, and an arcane or divine caster.

Cost: 10,000 gp.

Try our optional new Exhaustion rules on page 3.

Sphere of Annihilation

Source Game Master’s Guide to Traps & Terrors

Magic Trap

Magical, impenetrable darkness fills the gaping mouth of a stone face carved into a wall. The face is traditionally that of a fiend, but it could be of any creature.

Radiates: Transmutation magic.

Related Traps: Alcove of Illusion, Arcane Archway, Magic Landmine, Teleport Trap.

Trigger: Any time a creature or object enters the mouth of the stone face.

Spot: The face is easy to see and requires no check.

No sound issues from it and no light can illuminate the inside of it. A successful DC 20 Arcana check reveals that the mouth contains a sphere of annihilation that can’t be controlled or moved. It is otherwise identical to a normal sphere of annihilation.

Disarm: N/A

Dimensions: The mouth is 2 feet in diameter and roughly circular.

Number of Uses: Limitless.

Reset: N/A

Effect: Any matter that enters the mouth is instantly obliterated, similar to a disintegration spell, but with no saving throw and the result is instant death, dismemberment (for a limb thrust inside), or destruction (for objects).

Options

To customize this trap, choose from the options below.

Magic Mouth: Some versions of this trap include a magic mouth to deliver an enticing or mocking message. A successful dispel magic (DC 18) removes this enchantment. This trap also radiates illusion magic when this option is applied.

Sympathetic Magic: All cold and transmutation magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 cold damage on a failed save regardless of whether it normally deals cold damage or not. This is the cold of the cosmic void, of outer space, and not that of winter.

Sympathy: Some versions of the trap include an enchantment placed on the stone face, such that specified creatures feel an overwhelming urge to approach it and crawl inside its mouth. This effect is otherwise like the sympathy aspect of the antipathy/ sympathy spell. A successful dispel magic (DC 18) removes this enchantment. This trap also radiates enchantment magic when this option is applied.

Teleportation Circle: The rarest version of this trap includes a teleportation circle in the mouth. Only creatures authorized by the trap-maker at the time of its creation may enter the mouth without being obliterated. Instead of encountering the sphere of annihilation, they teleport to a preset location well-known to the trap-maker. However, to anyone outside the mouth, it appears they were obliterated.

A clever villain could use this to its advantage by appearing to commit suicide, or to kill an important NPC by shoving it inside the mouth. A successful dispel magic (DC 18) deactivates the teleportation circle for 1 hour but does not remove it.

This trap also radiates conjuration magic when this option is applied.

Construction Time: This trap takes a month to build.

It requires a stonemason and an arcane caster with a sphere of annihilation.

Cost: 250,000 gp.

---

Statue Temple

Source Game Master’s Guide to Traps & Terrors

Magic Trap

This trap consists of three iron or stone statues on stone pedestals spaced evenly apart in the main chamber of a temple. The statues are made in the image of a deity and its servants. A distinctive Large golden gong and mallet hang from the center statue’s hands, which is the one cast in the deity’s likeness.

Radiates: The gong radiates conjuration magic (to summon the holy or unholy spirits that animate the statues).

Related Traps: Statue of Poison Darts, Statue Trap.

Trigger: When the gong is struck by the mallet (or anything else), the trap activates. Optionally, the trap may activate without the gong being struck if the temple is defiled or desecrated in some way.

Spot: No check is necessary to see the trap. There may be various symbols, murals, altars, or clues in the room that might provide some insight into the nature of the trap. If there is, allow a DC 15 Arcana or Religion check to provide some useful information of the GM’s choice.

Disarm: Casting dispel magic (DC 18) on the gong while the statues are animated stops them in their tracks and disarms the trap for a number of rounds equal to the caster’s spell casting ability score modifier; after this time’s up, the statues return to life and continue their attack, or resume their original positions if there are no targets left in their location.

Dimensions: The statues are Large, as is the gong.

The mallet is Medium (or Large, if the typical creature striking it is also Large).

Number of Uses: Limitless, unless the statues are destroyed or the gong and/or mallet are removed.

Reset: The trap automatically resets itself (see below).

Effect: Activation of the trap requires all creatures present to roll initiative. The trap rolls initiative with a +8 bonus. The statues reveal themselves to be iron or stone golems (GM’s choice, MM). The golems attack any unauthorized creatures present except the one who rang the gong. They pursue the others throughout the building or complex as best they can, assuming they can fit through the rooms and corridors.

The golems are ordered not to harm or leave the building and must return to their original positions in 10 minutes. If the creature that rung the gong is still in the room when they return, they will attack it for as long as it remains in the room. The golems then return to their original positions.

For the next 3 hours, if anyone enters the room, the golems do not need the gong to be rung to animate; they wait until the creatures are close, then spring back to life and attack as before. After that, the spirits animating them depart and the trap resets.

Options

To customize this trap, choose from the options below.

Empowered Center Golem: The center golem can use the gong as a +2 shield to increase its armor class by +4 or to shield bash creatures with an extra +2 bonus to its attack rolls. It can also throw the gong like a +2 chakram. The basic weapon rules for a nonmagical chakram are reprinted for your convenience, but the Large version here deals the golem’s normal damage both in melee and when thrown. The gong is Large and heavy and can only be properly used as a shield by Large or Huge creatures. If the trap is disarmed, or the central statue is destroyed, it loses its magic. With this option applied to the trap, the gong radiates transmutation magic.

Sympathetic Magic: If the statue is dedicated to or depicts a deity, demigod, or warlock patron, any magic cast by worshippers of that entity within 120 feet of this trap has its DC increased by +1 and deals an extra 1d4 necrotic or radiant damage (caster’s or deity’s choice) on a failed save regardless of whether it normally deals force damage or not. The golems do not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap takes 180 days for stone golems or 360 days for iron golems.

These costs are the same for new construction or existing construction (assuming the statues fit inside and have enough room to move). It requires an engineer, stonemason, blacksmith, sculptor, and divine caster. The time to construct (or retrofit) the rest of the temple is not included. In addition, planar ally must be cast over the gong once per day for six consecutive days to bind the spirits to the statues.

The spirits are not bound in the conventional sense, as they are only present after the gong is struck and are free to depart once they have completed their assigned task. These are not conventional “always on” golems, and the spirits are willing and stable, which is factored into the cost as a discount over traditional golem construction (see manual of golems, DMG).

The planar ally spell must always be cast at dawn, noon, or midnight (depending on the religion), and always after completing a sacrifice worthy of the goal and reasonable for the religion. For example, an evil religion might require the ritual sacrifice of a living humanoid, whose blood is smeared over the statues and gong.

Cost: 150,000 gp for three stone golems or 250,000 gp for three iron golems. Cost includes the +2 gong/ shield/chakram and mallet, plus three stone pedestals for the statues to stand on.

---

Statue Trap

Source Game Master’s Guide to Traps & Terrors

Magic Trap

This trap involves a statue that has been enchanted to deliver a blast of magical energy to intruders. The statue can be of anything; the most common versions are rather obvious, and look like a roaring dragon, preaching cleric, or a wizard casting a spell.

Radiates: Evocation magic (or conjuration for acid or poison).

Related Traps: Statue of Poison Darts, Statue Temple

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 15 Perception check spots the pressure plate and/or reveals faint scorch (or other blast) marks on the floor and walls.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered. A successful dispel magic (DC 13) cast on the statue destroys the trap.

Dimensions: A single Medium-Huge statue that typically takes up a single 5- or 10-foot square. It may or may not be elevated off the floor by a stone dais or platform.

Number of Uses: Limitless.

Reset: Automatic.

Effect: The statue releases a 30-foot cone of fire or other magical damage type (GM’s choice). Each creature in the area must make a DC 13 Dexterity saving throw, taking 22 (4d10) fire (or other) damage on a failed save, or half as much damage on a successful one.

Options

To customize this trap, choose from the options below.

Linked Statues: This links multiple statues (usually arranged in corners or a circle) to all fire off their effect(s) at the same time from a single triggering of the pressure plate. Each statue may deal a different damage type, the same, or some other effect (such as the Web Statue, below).

Swarm Statue: Instead of damage, this version of the trap summon a swarm (MM, GM’s choice of creature).

Talking Statue: In addition to dealing its normal damage, this trap include a magic mouth to deliver some enticing or mocking message. A successful dispel magic (DC 18) removes this enchantment.

Web Statue: Instead of dealing damage, this trap casts web. This statue may be paired with a second statue that deals fire damage to light the web on fire.

Sympathetic Magic: All magic of the damage type cast by the statue(s) within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 damage of that type on a failed save regardless of whether it normally deals fire damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Not counting the month or more required to sculpt a statue from scratch (which isn’t necessary, as any statue will do), it takes an arcane or divine caster 3 weeks to complete this trap by casting a 1st-level or higher spell of the desired damage type into the statue three times a day, every day, at dawn, noon, and midnight.

Cost: Not counting the statue and any platform it may rest on, this trap costs 3,000 gp for the hired caster’s time.

Teleport Trap

Source Game Master’s Guide to Traps & Terrors

Magic Trap

A teleport trap is designed to quickly and efficiently transport creatures from one location to another of the trap-maker’s choosing—usually a more perilous one. It is a powerful tool of transference, as it can potentially move multiple creatures simultaneously, making it ideal for kidnapping or transporting large amounts of valuable goods.

Radiates: Conjuration magic.

Try our optional new Exhaustion rules on page 3.

Related Traps: Alcove of Illusion, Arcane Archway.

Trigger: This trap is triggered when a living creature steps either on, into, or through it.

Spot: A successful DC 15 Perception check reveals certain telltale signs such as strange symbols etched into stone walls or floors, or the presence of an unusual arcane object or spellcasting focus.

Disarm: Disarming this trap requires a successful DC 17 Arcana check. It should be noted that this trap cannot be disarmed with physical force alone—it must be neutralized using either magic or special tools designed for the purpose.

It can be temporarily disarmed by casting dispel magic (DC 18) for a number of minutes (or hours, at the GM’s discretion) equal to your arcane spellcaster level + your spellcasting ability score modifier, or, if you have no arcane spellcaster levels, then it is dispelled for a number of rounds equal to your Intelligence, Wisdom, or Charisma modifier (minimum of 1, use whichever score is higher).

Dimensions: One doorway, gate, archway, alcove, dais, pit, trapdoor, or enterable object (such as a coffin, iron maiden, or sarcophagus), or any wood or stone floor capable of bearing the necessary arcane symbols.

Assume a base size of 10-feet tall and 5-feet wide, but this can be adjusted up to 20-feet tall and wide to accommodate Huge creatures, or simply more creatures of Large-size or smaller.

Number of Uses: This trap can only be safely used a number of times per day equal to the Intelligence or Charisma modifier (minimum of 1) of the arcane caster who created it. If the creator is unknown, assume 3 times per day as the default maximum.

Attempting to activate this trap more than that in a 24 hour period will cause it to overload and explode violently (dealing 8d6 force damage to all creatures within 10 feet, and 4d6 force damage to all creatures within 30 feet). The trap is destroyed at that point.

Reset: After each use, this trap powers down for a short rest before resetting. During this time, creatures are free to enter and/or pass through the trap without triggering it.

Effect: When activated, this trap creates a 5-foot wide, 10 foot tall (or larger) cube centered on the trap area that teleports any creature inside it–along with any objects they are carrying–instantly across vast distances (up to 100 miles) on the Material plane. The exact destination is set by the trap-builder. Depending on the trap-maker’s intentions, there may be clues available that hint where the transported creatures end up. This effect functions in all other respects as a teleportation circle.

Choose or roll 1d12 on the table below to determine where creatures are teleported:

Options

To customize this trap, choose from the options below.

Sympathetic Magic: All conjuration magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 force damage on a failed save regardless of whether it normally deals force damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this type of trap requires extensive knowledge in both engineering and arcane magic. It takes 3 weeks for experienced craftsmen/wizards working together to build this device, including casting teleportation circle 7 times each at both the area of departure and arrival. Once set, the departure and arrival coordinates cannot be changed; any attempt to do so destroys the trap as detailed for exceeding its maximum uses per day above.

Cost: Building a teleport trap costs 10,000 gp for a standard 5-foot wide, 10-foot tall cube. For each additional 5-feet added to width or height, add an additional 10,000 gp to the cost. For example, a 10- foot wide by 10-foot tall cube costs 20,000 gp.

---

Wall of Force

Source Game Master’s Guide to Traps & Terrors

Magic Trap

This trap magically forms an invisible wall of force within 60 feet of its trigger.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap, nor do creatures immune to force damage.

Spot: A successful DC 15 Perception check reveals a discolored floor stone (the pressure plate).

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

Casting dispel magic (DC 18) on the trigger disarms the trap for 1 hour.

Dimensions: The wall appears in an orientation of the trap-maker’s choice (preprogrammed at the time the trap was installed), as a horizontal or vertical barrier or at an angle. It can be free floating or resting on a solid surface. It can form into a hemispherical dome or a sphere with a radius of up to 10 feet, or it can shape a flat surface made up of ten 10-foot-by-10- foot panels. Each panel must be contiguous with another panel. In any form, the wall is 1/4 inch thick.

Number of Uses: One, until reset.

Reset: The trap automatically resets itself after deactivating the wall. It can be used an unlimited number of times per day, but can only create and maintain only one wall of force per activation.

Effect: If the wall cuts through a creature’s space when it appears, the creature is pushed to one side of the wall (its choice which side).

Nothing can physically pass through the wall. It is immune to all damage and can’t be dispelled by dispel magic. A disintegrate spell destroys the wall instantly, however. The wall also extends into the Ethereal Plane, blocking ethereal travel through the wall, but not astral travel. The wall lasts for until destroyed.

Options

To customize this trap, choose from the options below.

Sympathetic Magic: All Force magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 force damage on a failed save regardless of whether it normally deals force damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap usually takes about 4 weeks for new construction or double that to retrofit existing construction. It requires an engineer, and an arcane or divine caster.

Cost: 10,000 gp.

Wall of Ice

Source Game Master’s Guide to Traps & Terrors

Magic Trap

The trap magically forms a permanent opaque wall of ice on a solid surface within 60 feet of its trigger.

Related Traps: Entombed In Ice.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap, nor do creatures immune to cold.

Spot: A successful DC 15 Perception check reveals a discolored floor stone (the pressure plate) and/or subtle apertures in the area the wall appears from.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

Casting dispel magic (DC 18) on the trigger disarms the trap for 1 hour.

Dimensions: The wall is 1 foot thick and up to 30 feet long and 10 feet high, or it’s a hemispherical dome up to 20 feet in diameter.

Number of Uses: One, until reset.

Reset: The trap automatically resets 1/day at midnight, provided the wall has melted or been destroyed.

Effect: When the wall appears, each creature in its space is pushed out of it by the shortest route. The creature chooses which side of the wall to end up on, unless the creature is incapacitated. The creature then makes a DC 17 Dexterity saving throw, taking 30 (10d6) cold damage on a failed save, or half as much damage on a successful one. The wall lasts until destroyed, dispelled, or it naturally melts. If it is created in winter or a perpetually cold climate, it may not melt for months, if ever.

The wall can be damaged and breached; each 10-foot section has AC 5, 30 hit points, vulnerability to fire damage, and immunity to acid, cold, necrotic, poison, and psychic damage. If a section is destroyed, it leaves behind a sheet of frigid air in the space the wall occupied. Whenever a creature finishes moving through the frigid air on a turn, willingly or otherwise, the creature must make a DC 17 Constitution saving throw, taking 15 (5d6) cold damage on a failed save, or half as much damage on a successful one. The frigid air dissipates when the rest of the wall vanishes.

Icy Illumination: The wall sheds icy dim blue-white light in a 20 foot radius.

Options

To customize this trap, choose from the options below.

Brittle Cold: A creature that touches the trap or comes within 5 feet of it takes 4 (1d8) cold damage.

Any nonmagical weapon made of metal that interacts with the trap gains a thin coating of ice and becomes brittle. After dealing damage, the weapon takes a permanent and cumulative ?1 penalty to damage rolls. If its penalty drops to ?5, the weapon shatters and is destroyed, dealing 2 (1d4) slashing damage (as shrapnel) to its wielder and the creature it just hit.

Nonmagical ammunition made of metal affected by this trap is destroyed after dealing damage.

Sympathetic Magic: All Cold and Water magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 cold damage on a failed save regardless of whether it normally deals cold damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap usually takes about 4 weeks for new construction or double that to retrofit existing construction. It requires an engineer and an arcane or divine caster.

Cost: 6,000 gp.

---

Wall of Lightning

Source Game Master’s Guide to Traps & Terrors

Magic Trap

This trap magically forms a wall of lightning within 60 feet of the trigger.

Related Traps: Electrocution Door, Lightning Web.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap, nor do creatures immune to lightning damage.

Spot: A successful DC 15 Perception check reveals a discolored floor stone (the pressure plate).

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

Casting dispel magic (DC 18) on the trigger disarms the trap for 1 hour.

Dimensions: The wall appears in any orientation the trap-maker chose (preprogrammed at time of installation), as a horizontal or vertical barrier or at an angle. It can be free floating or resting on a solid surface. The wall can be up to 60 feet long, 20 feet high, and 1 foot thick, or a ringed wall up to 20 feet in diameter, 20 feet high, and 1 foot thick. The wall is opaque and lasts for the duration.

Number of Uses: One, until reset.

Reset: The trap automatically resets itself after deactivating the wall. It can be used an unlimited number of times per day. To disarm or manually reset the trap, a lever hidden inside a secret control panel nearby (and outside the sealed area) must be accessed.

This panel can be found and accessed with a successful DC 15 Investigation check.

Resetting the trap requires 1 minute for a creature with less than a 13 Strength score to pull the stubborn lever up, or half that time for a creature with greater Strength.

Effect: When the wall appears, each creature within its area must make a DC 17 Dexterity saving throw.

On a failed save, a creature takes 20 (4d10) lightning damage, or half as much damage on a successful save.

Both sides of the wall deal 20 (4d10) lightning damage to each creature that ends its turn within 10 feet of that side or inside the wall. A creature takes the same damage when it enters the wall for the first time on a turn or ends its turn there. The other side of the wall deals no damage. The wall lasts until dispelled or the trap is disarmed.

Wet creatures and those in metal armor save with disadvantage against this effect.

Options

To customize this trap, choose from the options below.

Knockback: On a failed save, the creature cannot proceed past the trap. It is shoved 10 feet straight back by the damage dealt, knocked prone, and stunned until the end of its next turn.

Sympathetic Magic: All Lightning and Thunder magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 lightning damage on a failed save regardless of whether it normally deals lightning damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap usually takes about 4 weeks for new construction or double that to retrofit existing construction. It requires an engineer and an arcane or divine caster.

Cost: 5,000 gp.

Wall of Necrotic Fear

Source Game Master’s Guide to Traps & Terrors

Magic Trap

The trap magically forms a wall of necrotic fear within 60 feet of its trigger.

Related Traps: Wall of Hands, Wall of Psychic Fear.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap, nor do creatures immune to necrotic damage.

Spot: A successful DC 15 Perception check reveals a discolored floor stone (the pressure plate) and/or necromantic symbols etched into the trap.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

Casting dispel magic (DC 18) on the trigger disarms the trap for 1 hour.

Dimensions: The wall appears in any orientation the trap maker chose (preprogrammed at time of installation), as a horizontal or vertical barrier or at an angle. It can be free floating or resting on a solid surface. The wall can be up to 60 feet long, 20 feet high, and 1 foot thick, or a ringed wall up to 20 feet in diameter, 20 feet high, and 1 foot thick. The wall is opaque and sheds dim sickly gray light in a 20 foot radius.

Number of Uses: One, until reset.

Reset: The trap automatically resets itself after ending the wall.

Effect: When the wall appears, each creature within its area must make a DC 17 Dexterity saving throw.

On a failed save, a creature takes 20 (5d8) necrotic damage and is frightened for 1 minute, or half as much damage on a successful save and is not frightened. Each turn, a frightened creature can make a new saving throw to negate the condition.

Both sides of the wall deal 20 (5d8) necrotic damage to each creature that ends its turn within 10 feet of that side or inside the wall. A creature takes the same damage when it enters the wall for the first time on a turn or ends its turn there. The wall lasts for 1 minute or until the trap is dispelled.

Options

To customize this trap, choose from the options below.

Shadow Synergy: Aberrations, fiends, undead, and creatures from the Shadowfell are immune to the wall’s effect. Undead that are within 10 feet of the wall cannot be turned or destroyed.

Sympathetic Magic: All Necromancy magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 necrotic damage on a failed save regardless of whether it normally deals necrotic damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap usually takes about 4 weeks for new construction or double that to retrofit existing construction. It requires an engineer and an arcane or divine caster.

Cost: 4,000 gp.

---

Wall of Psychic Fear

Source Game Master’s Guide to Traps & Terrors

Magic Trap

The trap magically forms a wall of psychic fear within 60 feet of its trigger.

Related Traps: Wall of Psychic Fear.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap, nor do creatures immune to psychic damage.

Spot: A successful DC 15 Perception check reveals a discolored floor stone (the pressure plate) and/or the enchantment symbols etched into the trap.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

Casting dispel magic (DC 18) on the trigger disarms the trap for 1 hour.

Dimensions: The wall appears in any orientation you choose, as a horizontal or vertical barrier or at an angle. It can be free floating or resting on a solid surface. You can make the wall up to 60 feet long, 20 feet high, and 1 foot thick, or a ringed wall up to 20 feet in diameter, 20 feet high, and 1 foot thick. The wall is transparent.

Number of Uses: One, until reset.

Reset: The trap automatically resets itself after ending the wall.

Effect: When the wall appears, each creature within its area must make a DC 17 Charisma saving throw.

On a failed save, a creature takes 20 (5d8) psychic damage and is frightened for 1 minute, or half as much damage on a successful save and is not frightened. Each turn, a frightened creature can make a new saving throw to negate the condition.

Both sides of the wall deal 20 (5d8) psychic damage to each creature that ends its turn within 10 feet of that side or inside the wall. A creature takes the same damage when it enters the wall for the first time on a turn or ends its turn there. The wall lasts for 1 minute or until it is dispelled.

Options

To customize this trap, choose from the options below.

Psychic Synergy: Aberrations, celestials, fey, and creatures with psionics are immune to the wall’s effect.

Sympathetic Magic: All Enchantment magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 psychic damage on a failed save regardless of whether it normally deals psychic damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap usually takes about 4 weeks for new construction or double that to retrofit existing construction. It requires an engineer and an arcane or divine caster.

Cost: 4,000 gp.

---

Wall of Radiance

Source Game Master’s Guide to Traps & Terrors

Magic Trap

The trap magically forms a wall of radiant light within 60 feet of its trigger. This light can appear as sunlight, moonlight, or starlight (see Cosmic Synergy, below).

Related Traps: Wall of Thunder.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap, nor do creatures immune to radiant damage.

Spot: A successful DC 15 Perception check reveals a discolored floor stone (the pressure plate) and/or the evocation symbols etched into the trap.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

Casting dispel magic (DC 18) on the trigger disarms the trap for 1 hour.

Dimensions: The wall appears in any orientation you choose, as a horizontal or vertical barrier or at an angle. It can be free floating or resting on a solid surface. You can make the wall up to 60 feet long, 20 feet high, and 1 foot thick, or a ringed wall up to 20 feet in diameter, 20 feet high, and 1 foot thick. The wall is opaque. It sheds bright light in a 30 foot radius and dim light for an additional 30 feet.

Number of Uses: One, until reset.

Reset: The trap automatically resets itself each day at dawn.

Effect: When the wall appears, each creature within its area must make a DC 17 Dexterity saving throw.

On a failed save, a creature takes 20 (5d8) radiant damage and is blinded for 1 minute, or half as much damage on a successful save and is not blinded. Each turn, a blinded creature can make a new saving throw to negate the condition.

Both sides of the wall deal 20 (5d8) radiant damage to each creature that ends its turn within 10 feet of that side or inside the wall. A creature takes the same damage when it enters the wall for the first time on a turn or ends its turn there. The wall lasts for 1 minute or until it is dispelled.

Radiant Light: The wall sheds bright light in a 30 foot radius and dim light for an additional 30 feet. This light can appear as sunlight, moonlight, or starlight.

Options

To customize this trap, choose from the options below.

Cosmic Synergy: Aberrations are immune to the moonlight and starlight versions of this wall. Celestials are immune to all versions of the wall’s effect.

Sympathetic Magic: All Celestial or Radiant magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 radiant damage on a failed save regardless of whether it normally deals radiant damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap usually takes about 4 weeks for new construction or double that to retrofit existing construction. It requires an engineer and an arcane or divine caster.

Cost: 3,000 gp.

~~~ MECHANICAL TRAPS ~~~

---

Acid Cauldron

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap consists of a large metal cauldron concealed in a pit or at the end of a chute. The cauldron is filled with an acidic substance such as acid or caustic alkaline. The substance may be calm or it may bubble, boil, and steam even before it has made contact with a victim. Regardless, it has an acrid, chemical stench.

Related Traps: Chute, Flood Zone, Pit (Flooded), Quickslime, Quickslime Geyser, Wall of Acid.

Trigger: The trap is triggered by a creature or object that enters its area of effect.

Spot: The trap can be detected with a DC 10 Perception check when unconcealed. When concealed, it may not be detectable except by its acrid odor (DC 15 Perception), but even if it is noticed, the trap’s location may be hard to determine (DC 15 Investigation).

Disarm: This trap can only be disarmed by a creature emptying the acid cauldron. Once disarmed, it remains so until the cauldron is refilled with acid or a similar caustic substance. However, most cauldrons are securely bolted to the floor to prevent accidents. Some may be chained in place to a beam in the ceiling, and thus limited in what direction they can pour.

Dimensions: Due to the cost and the dangers involved in transporting the acid to the trap location, many acid traps are only 5-feet wide and 5-feet deep (about the size of a typical industrial cauldron). The next most common design is 10-feet wide by 10-feet deep.

Larger versions (in width and/or depth) exist.

Number of Uses: Limitless, as long as it remains full.

Reset: It takes a single creature 1 hour to safely and slowly refill the cauldron with acid, or a team of two or more half that time.

Effect: Falling creatures take the normal 1d6 bludgeoning damage per 10 feet fallen, plus an extra 1d6 bludgeoning damage from ramming into the hard metal cauldron. If the trap is triggered by a chute instead, sliding creatures only take 1d6 bludgeoning damage from hitting the cauldron regardless of how long or angled the chute that delivered them into the cauldron is.

The liquid contained in these traps varies depending on who set it up; some contain cheap caustic alkalines such as lye, while others may contain rarer and deadlier corrosive acids like hydrochloric acid, nitric acid, or sulfuric acid (see below). The stronger the acid, the more powerful its effects will be. In this way, you can scale the trap’s damage to fit your needs.

The acid can also corrode most objects, destroying them if they are not protected by magical or nonmagical means of protection such as glass, waxes, or oils (see below by acid type).

Once in the cauldron, a creature takes acid damage for every round they remain inside regardless of whether it is fully or partially submerged, and half damage for the first 3 rounds after it escapes the acid.

Choose your favorite acid or caustic substance, or roll 1d6 on the table below:

Lye: 1d4 acid damage per round in the cauldron and 1d2 acid damage for the first 3 rounds after the creature or object escapes. A creature takes half damage on a successful DC 11 Dexterity saving throw. If the save fails by 5 or more, acid gets in its eyes and the creature is blinded until it or another creature spends an action to wash out its eyes. If its eyes are not washed within 1 minute, the blindness becomes permanent. Lye is also known as caustic soda or sodium hydroxide. This is the most common, least dangerous, and cheapest acid.

Hydrochloric Acid: 1d6 acid damage per round in the cauldron and 1d3 acid damage for the first 3 rounds after the creature or object escapes. If the save fails by 5 or more, acid gets in its eyes and the creature is permanently blinded. If the save fails by 5 or more, the creature is permanently blinded.

d6	Acid Type
1-3	Lye
4	Hydrochloric Acid
5	Sulfuric Acid
6	Nitric Acid

In addition, any creature that requires air to breathe that ends its turn inside or adjacent to this trap (within 5 feet) must make a successful DC 13 Constitution saving throw or become poisoned by the toxic fumes. Every round after it remains outside this range, it may make a new saving throw to negate the condition until it succeeds. Creatures that cover their nose and mouth while in range save with advantage. Creatures with acid immunity or resistance are immune to the fumes.

Hydrochloric acid melts stone.

Sulfuric Acid: 2d4 acid damage per round in the cauldron and 1d4 acid damage for the first 3 rounds after the creature or object escapes. A creature takes half damage on a successful DC 13 Dexterity saving throw. If the save fails by 5 or more, acid gets in its eyes and the creature is permanently blinded. Nonmagical objects submerged in this acid are damaged in 2 rounds and destroyed in 5 rounds. Magic items are destroyed in 72 hours if left submerged.

In addition, any creature that requires air to breathe that ends its turn inside or adjacent to this trap (within 10 feet) must make a DC 15 Constitution saving throw or become poisoned by the toxic fumes. Every round after it remains outside this range, it may make a new saving throw to negate the condition until it succeeds. Creatures that cover their nose and mouth while in range save with advantage. Creatures with acid immunity or resistance are immune to the fumes.

Sulfuric acid melts most common metals, but not stone, so it must be stored in a cauldron made of exotic metal like Zirconium or Tantalum, or else in a stone pit.

Nitric Acid: 2d8 acid damage per round in the cauldron and 1d8 acid damage for the first 3 rounds after the creature or object escapes. A creature takes half damage on successful DC 14 Dexterity saving throw. If the save fails by 5 or more, acid gets in its eyes and the creature is permanently blinded. Nonmagical objects submerged in this acid are damaged in 1 round and destroyed in 3 rounds. Magic items are destroyed in 24 hours if left submerged.

In addition, any creature that requires air to breathe that ends its turn inside or adjacent to this trap (within 20 feet) must make a DC 17 Constitution saving throw or become poisoned by the toxic fumes. Every round after it remains outside this range, it may make a new saving throw to negate the condition until it succeeds. Creatures that cover their nose and mouth while in range save with advantage. Creatures with acid immunity or resistance are immune to the fumes.

Nitric acid melts stone. It is the only acid that melts all metals (except gold and platinum), so it must be stored in a costly cauldron lined with gold or platinum.

Options

If you’d like to customize this trap, choose from the options below.

Chute vs. Pit Delivery: If it was a chute trap that delivered the creature into the acid instead of a pit, a successful DC 15 Dexterity saving throw will allow a creature in the cauldron to pull itself back out onto the chute… unless a metal grille (see Portcullis) or stone wall slammed down behind them. Pits that lead to acid cauldrons usually require magic or the assistance of others to escape.

Sympathetic Magic: All Acid and Water magic cast within 30 feet of an acid cauldron has its DC increased by +1 and deals an extra 1d4 acid damage on a failed save regardless of whether it normally deals acid dam-age or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: 1 hour to install the cauldron if unsecured, and 3 hours if bolted to the floor, plus 1 hour to safely pour the acid. This allows a slow and accurate pour that reduces toxic fumes to the workers.

Note that transporting acid in such vast quantities is its own hazard with a timetable subject to GM discretion. Time to construct the pit or chute to house the acid cauldron is not included (see Chute or Pit).

Cost: Enough acid to fill the cauldron costs 50 gp for lye, 250 gp for hydrochloric acid, 500 gp for sulfuric acid, and 1,000 gp for nitric acid. These costs include the cost of the cauldron required to store that type of acid (up to 10 feet wide and deep).

---

Alchemist’s Inferno

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap consists of an alchemist’s laboratory set up in a room. It appears to be brewing 3 magic potions by the look and smell of what’s in the vials. These potions are bubbling over 3 small open flames. The vials contain colored water, poison, or are possibly real (but unfinished) potions, depending on whether the lab was recently in use by an alchemist who had to leave in a hurry, or if it’s a “dummy lab” set up solely as a trap.

Related Traps: Wall of Acid, Wall of Paralyzing Poison Mist, Wall of Petrifying Poison Gas, Wall of Fire.

Trigger: The trap is triggered by any Small or larger creature that touches the tripwire, which is a thin wire strung from one side of the area to the other. Tiny or incorporeal creatures do not activate the trap.

Spot: The tripwire is 3 inches off the ground and stretches between two support beams. A successful DC 10 Perception check reveals the tripwire in bright light, while DC 13 spots it in dim light. DC 15 spots a tripwire in nonmagical darkness or concealed below murky water.

Disarm: A successful DC 15 Dexterity saving throw using thieves’ tools breaks the tripwire harmlessly. A character without thieves’ tools can attempt this check with disadvantage using any edged weapon or edged tool. On a failed check, the trap triggers.

Disarming the tripwire doesn’t disarm the gas valve. A successful DC 15 Arcana or Investigation check can disarm the gas portion of the trap by removing the potions if made by a creature proficient in Arcana. This requires finding the correct valve in a complex network of pipes and then turning it off. If this check fails, the trap activates as normal.

Dimensions: The trap fits any room that can house the laboratory, with a 20 by 20 foot minimum size.

Number of Uses: One, if it explodes.

Reset: Resetting a disarmed trap takes 1 minute for a single creature or half that time for a team of two; however, anyone resetting the trap must be proficient in Arcana. The trap can’t be reset after it detonates.

Effect: Once triggered, the trap releases an odorless, colorless gas that is highly flammable. The gas ignites, causing an explosion that releases thick black smoke and poison fumes throughout the room. The smoke and fumes spread around corners.

All creatures within 30 feet take 4d10 fire and 2d10 poison damage (DC 15 Dexterity saving throw for half damage) and creatures 31-60 feet away take 2d10 fire and 1d10 poison damage. A creature that fails this save is knocked prone by the blast.

All creatures must then make an additional DC 15 Constitution saving throw or be poisoned until they finish a long rest; this is due to inhaling poisonous smoke and toxic fumes from explosion. Furthermore, any creature that fails this save also suffers 1 level exhaustion due to smoke inhalation.

Options

If you’d like to customize this trap, choose from the options below.

Sympathetic Magic: All Acid, Poison, and Water magic cast within 30 feet of an alchemist’s lab (prior to its explosion) has its DC increased by +1 and deals an extra 1d4 acid damage on a failed save regardless of whether it normally deals acid damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap takes 10 minutes, assuming the lab already exists. To build a new lab from scratch takes 1 month and requires an engineer and alchemist or arcane caster.

Cost: The “dummy lab” trap costs 500 gp for all required materials such as pipes, valves, timers and explosive vials necessary to construct the trap correctly. A real, fully functional alchemist’s lab costs whatever that costs in your game (1,000 gp minimum).

---

Ankle Biter

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

The trap consists of a sinking pressure plate set into a stone floor, connected to a spring-loaded spear trap in the wall. It is designed to injure and slow an intruder rather than to kill.

Related Traps: False Staircase, Foot Trap, Magic Landmine, Spiral Staircase.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 15 Perception check reveals indentations around the pressure plate. A second successful check reveals the secret panel in the wall that houses the spear.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

Dimensions: One 5-foot square of stone passageway and a recessed compartment in its adjoining wall that holds the spring-loaded spear.

Number of Uses: One, until manually reset.

Reset: To reset this trap, a creature must succeed on a successful DC 13 Strength check to wind the stubborn spear back into its secret compartment.

Effect: When triggered, the spring-loaded half-spear launches out from its adjacent hidden wall panel at the same time. The trap is designed to strike Medium-size targets below the knee, specifically targeting their ankles. Small creatures are targeted around the knee or upper leg.

The creature that triggered the trap must make a successful DC 13 Dexterity saving throw to avoid being hit by the spear. If failed, the spear strikes it in the lower leg if Medium (or upper leg if Small) and deals 1d8 piercing damage. The injured creature’s land speed is reduced by half until it receives magical healing or completes a long rest, and it can no longer take the Dash action until its injury is healed. If the trap is located on a staircase and the creature’s saving throw fails, it falls down the stairs and takes an extra 1d6 bludgeoning damage per 10 feet it falls. If there is an option to fall off the stairs instead, this occurs if the saving throw was failed by 5 or more.

Otherwise, the creature manages to stay on the stairs.

Options

If you’d like to customize this trap, choose from the options below.

Bleeder: The wounds caused by this trap continue to bleed. On each round after the initial injury occurred, the wounded creature continues to lose 1 hit point per round until it or another creature spends an action to bind the wound(s) caused by the trap. Magic healing also ends this effect. While bleeding, the wounded creature leaves a trail of blood behind it that grants advantage to all rolls made to track it.

Diseased Spear: The spear has not been cleaned of the gore from its previous victims. A creature hit by it must make a DC 11 Constitution saving throw or be infected with sewer plague.

Poison Spear: The spear deals an extra 1d6 poison damage and the target is poisoned until it completes a long rest.

Rusty Spear: The spear is rusty and deals an extra 1d6 necrotic damage.

Tripping Hazard: The spear remains extended until reset. This creates a tripping hazard for any creature moving through its square. A creature that does must make a successful DC 11 Dexterity saving throw to avoid being knocked prone. If the creature was running and/or the passage is in dim light, the DC increases to 13. If the creature was running and fails its saving throw, then it also takes 1d3 bludgeoning damage in addition to being knocked prone.

Construction Time: Constructing this trap takes 2 weeks for new construction or double that time if retrofitting existing construction. It requires an engineer and stonemason along with a blacksmith.

Cost: This trap costs 250 gp, plus any poison.

---

Ballista Corridor

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This hallway trap fires a ballista bolt that strikes every creature in its path. A ballista is a Huge crossbow, a siege weapon primarily used in rooftop or tower defense. Treat it as a Huge heavy crossbow in terms of weapon properties and triple its range (300/900).

The weapon is usually concealed behind a wall with a Huge crossbow slit in it. If the weapon is manned, then this wall also provides total cover to its crew.

Related Traps: False Door, Guillotine Door, Lightning Web, Pendulum Gauntlet.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 15 Perception check reveals the pressure plate but not its function, as the hole in the wall through which the ballista looses its bolt is at the end of the corridor. If the GM wishes, evidence of past ballista strikes may be visible at the point of impact, or thick splintered table or similar large pieces of “test” wood may be found nearby to provide clues.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

The hidden room that houses the ballista can be found with DC 17 Investigation check, and the trap disarmed from inside there with a successful DC 13 Dexterity saving throw using thieves’ tools.

Dimensions: The trap is designed to fit any corridor 5-feet to 10-feet wide and at least 50-100 feet long.

The crossbow slit in the wall is large enough to easily loose the bolt, and the hidden room that houses the trap is large enough to house the Huge weapon.

Number of Uses: One, until manually reset.

Reset: Resetting takes 2 minutes for a single creature or half that time for a team of two or more.

Effect: Activation of the trap requires all creatures present to roll initiative. The trap rolls initiative with a +8 bonus. Once triggered, a large steel-tipped bolt is loosed from the hidden ballista (or an equivalent spring-loaded mechanism built into the wall).

The bolt shoots down the middle of the corridor at to 60 feet per round). Any creature or object in its path that fails a DC 15 Dexterity saving throw takes 6d6+6 piercing damage and is knocked prone and stunned until the end of its next turn. A creature that chooses to drop prone rather than dodge the bolt gains advantage on its saving throw. If the corridor is only 5-feet wide, the saving throw DC is increased to 17 as there is less room to avoid the missile and more chance of other creatures getting in the way. Once the bolt impacts the far wall, it stops, embedding itself in the wood or stone.

Options

If you’d like to customize this trap, choose from the options below.

Bleeder: The wounds caused by this trap continue to bleed. On each round after the initial injury occurred, the wounded creature continues to lose 1 hit point per round until it or another creature spends an action to bind the wound(s) caused by the trap. Magic healing also ends this effect. While bleeding, the wounded creature leaves a trail of blood behind it that grants advantage to all rolls made to track it.

Diseased Bolt: The bolt has been coated in the blood and fluids of diseased creatures. A creature hit by it must make a DC 11 Constitution saving throw or be infected with sewer plague.

Poison Bolt: The bolt deals an extra +10 poison damage and the target is poisoned until it completes a long rest.

Rusty Bolt: The bolt is rusty and deals an extra +10 necrotic damage.

Construction Time: Constructing this trap usually takes about 2 weeks for new construction or double that to retrofit existing construction. An engineer and stonemason are required.

Cost: Each trap costs 500 gp for new construction or double that for existing construction plus 250 gp for the ballista and 30 bolts.

---

Boulder Drop

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap consists of a concealed boulder weighing several hundred pounds suspended 30 feet off the ground by a complex rope and pulley system. It is usually concealed above a strategic doorway or passageway to close off access, as well as to kill intruders.

Related Traps: Cave-In, Collapsing Roof, Crumbling Ledge, Crushing Walls, Log Jam, Rolling Sphere.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap.

Spot: To spot this trap requires a successful DC 15 Perception check. This reveals what appears to be a large disguised circular hole or passage in the ceiling (approximately 25 feet across), but it may not be obvious what it does or what is concealed above it.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

Dimensions: The Huge boulder is 20-feet across in diameter and designed to fit within the stone room and/or passageway beneath it. It is roughly flat-bottomed, and not designed to roll. Anything within the area where the boulder drops is at risk of being crushed.

Number of Uses: Once, until reset.

Reset: Not unless the boulder can be returned to its starting position by its rope and pulley system. This requires 1 hour and a team of a dozen creatures with 13 Strength or more.

Effect: When triggered, any creature within a 20- foot radius of the trap must make a DC 15 Dexterity saving throw or be struck by the boulder. The boulder deals 55 (10d10) bludgeoning damage when it drops. In addition, any creature struck that fails its save is knocked prone, restrained (partially pinned), and stunned until the end of its next turn. In addition, it takes 1 level of exhaustion. Restrained creatures cannot free themselves. It requires a single creature with 18 Strength or 2 or more creatures with 16 Strength or better to shift the boulder enough to free a pinned creature, using all their actions and losing any reaction while they do so. A successful save results in half damage, but the creature loses its reaction until its next turn. It is not knocked prone, restrained, or stunned, and does not suffer 1 level of exhaustion. It is forced to move a minimum of 5 feet outside the squares occupied by the boulder. If a creature has insufficient movement left to escape the boulder, then the saving throw cannot succeed and it takes the full damage and effects of a failed saving throw.

Options

If you’d like to customize this trap, choose from the options below.

Rockpile: This version of the trap consists of a reinforced chain net holding many Small to Large rocks instead of one Huge boulder. It deals half as much damage as the boulder (5d10), but does so over up to a 40 foot sphere. The terrain affected by the rock pile becomes difficult terrain.

Construction Time: Constructing this trap takes 4 weeks and requires an engineer and stonemason.

Cost: 1,000 gp.

---

Bridge of Sorrows

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap consists of a rickety rope suspension bridge spanning a large chasm over a pit, river, or other hazardous or creature-infested terrain. It is made from uneven planks of wood that creak and shift with each step taken. It has a frayed rope handrail along each side.

Related Traps: Broken Bridge.

Trigger: The trap is triggered at random by placing 20 pounds or more of pressure on any of the planks.

Whenever a creature moves across the bridge in any direction, it must make a DC 13 Dexterity saving throw for every 5 feet traveled. This assumes it is walking slowly and carefully while holding both handrails. If it is only holding one handrail (such as to hold a shield, swing a sword, or cast a spell), the DC increases to 14. If a creature attempts to run, fight, or grapple on the bridge, then the DC increases to 15.

On a success, the planks hold (for now). On a failure, one of the planks breaks and the trap triggers.

For every 10 feet a creature moves on the bridge, roll a d6. On a roll of 1, the next plank is either completely gone or uselessly hanging by a thread. The creature has two choices if it is to continue:

1. It must perform a standing long jump to the next plank and hope it holds (DC 15 Dexterity saving throw to succeed);
2. It must inch along the rope handrails past the missing plank and reduce its speed to 5 feet that round, losing its reaction, but automatically succeeding unless it is hit by an attack (DC 8 + damage dealt not to fall off).

If the creature jumps and fails, the plank they land on breaks and the creature falls through the bridge unless it makes a DC 15 Strength or Dexterity saving throw (whichever is better). If it succeeds, it manages to hang onto the adjacent planks. It is restrained and can make a new saving throw each round to pull itself up onto the bridge but is knocked prone in the process. A creature can make as many additional saves to pull itself up as it has a positive modifier to its Strength or Dexterity score (minimum of 1). After that, it loses its grip and falls.

Spot: No check is needed to notice this bridge is old, poorly made, and a gamble to cross. A successful DC 13 Investigation check reveals that the safest course (short of turning back) is to take the bridge slowly, one creature at a time, moving at 5 foot intervals to carefully test each plank before proceeding, and to use both handrails.

Disarm: A mending cantrip reduces the DC to 10 for walking slowly across the bridge using both handrails, or to DC 11 for walking slowly using only one handrail, or to DC 13 for running, fighting, or grappling on the bridge. See also Destroy, below.

Dimensions: The bridge spans a minimum of 50 feet in length, but only 5 feet in width.

Number of Uses: Limitless, as long as it holds.

Reset: N/A

Effect: When triggered, the bridge shakes and shifts violently. The creature that triggered it must make a DC 15 Dexterity saving throw as the plank under it breaks; on a success, the creature’s foot falls through the gap, but it is able to recover its balance. This takes all its actions that turn and it loses its reaction.

On a failure, the creature is knocked prone, but does not fall off the bridge. It also ends its movement for that round. If the save fails by 5 or more, the creature falls, taking the appropriate falling damage from the bridge’s height, and facing whatever other dangers await below (crocodiles, drowning, jagged rocks, lava, etc.).

Any other creatures on the bridge at the time must make a DC 13 Dexterity saving throw or be forced to stop and end their movement for the round. A creature that successfully crosses the bridge by foot suffers 1 level of exhaustion from undergoing the sheer anxiety of the experience. Creatures that flew, teleported, or used other magic to successfully cross do not suffer this exhaustion.

The entire length of the bridge counts as difficult terrain.

Falling Off the Bridge: An adjacent creature (within 5 feet) can attempt to catch another creature (or object) falling off the bridge. This requires two saving throws: a DC 13 Strength saving throw to catch the creature or object before it falls, followed by a DC 13 Dexterity saving throw to prevent itself from falling.

This second saving throw is required regardless of whether the first succeeds or not. If the second save succeeds, the creature is now holding onto the creature or object with one hand, and holding onto one of the rope handrails with the other. On its next turn, it can repeat these saving throws to secure both their positions. If it does, that uses all its actions; it cannot move that turn and loses its reaction.

A grappled creature can be shoved off the bridge by making a successful melee attack roll against it. The shoved creature is allowed a DC 15 Dexterity saving throw to catch itself before falling; if the save succeeds, it is not shoved off the bridge. If the save fails, it catches one of the planks and is hanging on with one or both hands (it drops whatever it was holding if possible). If the save fails by 5 or more, the creature loses its grip and falls off the bridge. A creature that is incapacitated, killed, or rendered unconscious on the bridge falls off it. It receives no saving throw to prevent this. A creature that is paralyzed or stunned on the bridge must make a DC 15 Dexterity saving throw with disadvantage to prevent falling off. If it succeeds, it grabs the handrails and cannot be shoved off while it remains paralyzed or stunned. It also imposes disadvantage on the Strength and Dexterity saving throws of adjacent creatures trying to move around it. A creature that is petrified on the bridge becomes too heavy for the bridge to support its new weight; it falls through the planks, taking 1d3 planks out with it. It receives no saving throw to prevent this.

DESTRUCTION

The bridge can be destroyed by dealing 30 points of acid, fire, lightning, slashing, or thunder damage to the twin posts holding it together at either end, or 20 points of the same damage types to any point in between. The bridge is vulnerable to acid, fire, force, lightning, and slashing damage. If the bridge is destroyed, all creatures on it may fall off, depending on whether it is severed at one of its sides or closer to its center.

The worst outcome is for a center or near-center collapse, and to be located anywhere near it. Those creatures fall with no saving throw, while creatures within 30 feet of either side must succeed at a DC 17 Dexterity saving throw to avoid falling. If the save succeeds, they take 4d6 bludgeoning damage but hold on to the bridge with both hands, dropping anything they were carrying. If the bridge is severed on one side, all creatures on the severed side fall from the bridge with no saving throw unless they were within 10 feet of the severed end. Creatures within 10 feet of the severed side must succeed at a DC 17 Dexterity saving throw. If the save succeeds, they are able to get across the bridge before it falls.

Creatures within 30 feet of the far side (still attached to the twin posts) must also succeed at a DC 17 Dexterity saving throw. If the save succeeds, they each take 3d6 bludgeoning damage but hold onto the bridge with both hands, dropping anything they were carrying.

Creatures still hanging onto the attached end of the bridge can make a DC 15 Strength saving throw each round to pull themselves up 5 feet. If the check fails, they don’t move. If the save fails by 5 or more, they fall off the bridge, possibly hitting creatures on the bridge below them. Creatures below must make a DC 13 Dexterity saving throw to avoid being hit. On a failure, they take 1d6 bludgeoning damage and fall off the bridge too.

Options

If you’d like to customize this trap, choose from the options below.

Slippery: The bridge is wet from rain, snow, or slime. Increase all check and saving throw DCs on the bridge by +2.

Sympathetic Magic: All Air, Lightning, and Thunder magic cast within 30 feet of this trap (or anywhere on it) has its DC increased by +1 and deals an extra 1d4 thunder damage on a failed save regardless of whether it normally deals thunder damage or not.

Construction Time: Constructing this trap usually takes 8 weeks for barbarians, hobgoblins, orcs, rangers, or tribal warriors. Most other creatures require 12 weeks. An engineer and woodworker are required.

Cost: This trap costs 1,000 gp when new for a bridge up to 120 feet long. When newly constructed, unless it was intended to be a trap, it is in good repair. It only becomes a trap when age, weather, or neglect intervene.

---

Broken Bridge

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap consists of a broken stone bridge spanning a large chasm over a chasm, lava, river, or other hazardous or creature-infested terrain. It was once an impressive feat of engineering, but has long since fallen into disrepair. The bridge may or may not have guard rails, or only irregular portions of them that remain.

Alternatively, you could replace the bridge with pillars, staircases, a ruined stone roof, etc. These options create a purely cosmetic change.

Related Traps: Bridge of Sorrows, Crumbling Ledge.

Trigger: The trap is triggered in one of two ways:

1. When two or more creatures engage in grappling or melee combat while on a bridge section; or 2. When a section is damaged by 30 points or more of magic or bludgeoning, lightning, force, or thunder damage.

Spot: No check is necessary to spot the bridge or recognize its glaringly obvious danger.

Disarm: N/A

Dimensions: The bridge is as long and wide as you need it to be. The bare minimum length is 30 feet long and 5 feet wide, but the typical broken bridge is 120 feet long and 20 feet wide.

Number of Uses: Limitless, until destroyed.

Reset: N/A

Jumping: Whenever a creature jumps from one section of the bridge to another in any direction, it must make an Athletics or Acrobatics check, with the DC depending on how far apart the sections are:

• 5 Feet Apart: DC 11
• 10 Feet Apart: DC 13
• 15 Feet Apart: DC 17
• 20 Feet Apart: DC 19

Creatures cannot make a running long jump farther than their Strength score. Large creatures reduce the DC for these jumps by -2. Huge or Gargantuan creatures cannot make the jump without collapsing the section they land on. Creatures wearing heavy armor or that are heavily encumbered roll with disadvantage. Creatures using jump, misty step, or similar magic do not need to make the check. If you jump more than half your Strength score in feet, you are knocked prone when you land. If the sections are at different heights (more common for a broken staircase or pillars than a bridge), then the rules for standing long jumps apply instead, and you can only move half as far.

Due to rubble, bones, debris, and/or uneven texture, each broken section of the bridge counts as difficult terrain.

Effect: When triggered, the affected bridge section shakes and violently collapses 1 round later, plunging itself and whatever remains on it to whatever waits below. Creatures on the collapsing section may use magic to escape or roll an Athletics or Acrobatics check with disadvantage to jump to the next section (if any), using the next highest DC due to the shaking:

• 5 Feet Apart: DC 13
• 10 Feet Apart: DC 15
• 15 Feet Apart: DC 19
• 20 Feet Apart: DC 21

A creature that successfully crosses the entire length of the bridge by foot suffers 1 level of exhaustion from undergoing the epic anxiety of the experience.

Creatures that flew, teleported, or used other magic to successfully cross do not suffer this exhaustion.

Falling Off the Bridge: An adjacent creature (within 5 feet) can attempt to catch another creature (or object) falling off the bridge. This requires two saving throws: a DC 13 Strength saving throw to catch the creature before it falls, followed by a DC 13 Dexterity saving throw to prevent itself from falling.

This second saving throw is required regardless of whether the first succeeds or not. If the second save succeeds, the creature is now holding onto the creature or object with one hand, and holding onto one of the rope guard rails with the other. On its next turn, it can repeat these saving throws to secure both their positions. If it does, that uses all its actions and it cannot move that turn and loses its reaction.

A grappled creature can be shoved off the bridge by making a successful melee attack roll against it. The shoved creature is allowed a DC 15 Dexterity saving throw to catch itself before falling; if the save succeeds, it is not shoved off the bridge. If the save fails, it catches the ledge and is hanging on with one or both hands (it drops whatever it was holding if possible). If the save fails by 5 or more, the creature loses its grip and falls off the bridge. A creature that is incapacitated, killed, or rendered unconscious on the bridge falls off it. It receives no saving throw to prevent falling. A creature that is paralyzed or stunned on the bridge must make a DC 15 Dexterity saving throw with disadvantage to prevent falling off. If it succeeds, it grabs the guard rail (if there is one) and, if it does, it cannot be shoved off while it remains paralyzed or stunned. If there is no guard rail, it can be shoved off, but otherwise stays in place unless the bridge section collapses.

Options

If you’d like to customize this trap, choose from the options below.

Slippery: The bridge is wet from rain, snow, or slime. Increase all check and saving throw DCs on the bridge by +2.

Sympathetic Magic: All Air, Lightning, and Thunder magic cast within 30 feet of this trap (or anywhere on it) has its DC increased by +1 and deals an extra 1d4 thunder damage on a failed save regardless of whether it normally deals thunder damage or not.

Construction Time: Constructing an intact bridge usually takes 6 months for deep gnomes, duergar, dwarves, and earth elementals. Most other creatures require 1 year. An engineer and stonemason are required.

Cost: An intact bridge costs 10,000 gp for a bridge up to 120 feet long. When newly constructed, unless it was intended to be a trap, it is in good repair. It only becomes a trap when age, weather, or neglect intervene.

---

Cave-In

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap is meant to imprison creatures in an underground area such as a cave, dungeon, mine, or sewer by collapsing the roof over its entrance. Optionally, it might be caused by earthquakes, thunder damage, etc.

Related Traps: Boulder Drop, Collapsing Roof, Crumbling Ledge, Crushing Walls, Log Jam, Rolling Sphere, Sinkhole.

Trigger: The trap is triggered by any Small or larger creature that touches the tripwire, which is a thin wire strung from one side of the area to the other. It is also triggered if 20 or more points of area effect damage is released in its vicinity, or half that amount for force, lightning, or thunder. Tiny or incorporeal creatures do not activate the trap.

Spot: The tripwire is 3 inches off the ground and stretches between two support beams. A successful DC 10 Perception check reveals the tripwire in bright light, while DC 13 spots it in dim light. DC 15 spots a tripwire in nonmagical darkness or concealed below murky water. Anyone who inspects the beams can easily deter-mine that they are merely wedged in place.

As an action, a character can knock over a beam, causing the trap to trigger. The ceiling above the tripwire is in bad repair, and anyone who can see it can tell that it’s in danger of collapse.

Disarm: A successful DC 15 Dexterity saving throw using thieves’ tools breaks the tripwire harmlessly. A character without thieves’ tools can attempt Try our optional new Exhaustion rules on page 3.

this check with disadvantage using any edged weapon or edged tool. On a failed check, the trap triggers.

Dimensions: The trigger itself takes up no more than a 10- to 20-foot area. The actual cave-in fills a 20-foot to 120-foot (2d6 x10) radius.

Number of Uses: One.

Reset: As long as the trap was only disarmed, not triggered, it can be reset in 10 minutes by a single creature with an engineering, mining, sapping, stonemason, or similar background that makes a successful DC 13 Investigation check. The DC for dwarves, duergar, deep gnomes, and earth elementals to reset this trap is only 11. If their check fails, nothing happens. If anyone else tries to reset it, a successful DC 17 Investigation check is required to do so, and it takes 1 hour. If this check fails, the trap is triggered.

Effect: Once triggered, several critical supports near the room or passageway’s entrance suddenly give way, collapsing the weight of the earth or stone ceiling onto anything below. All creatures within its area of effect (see Dimensions, above) must make a successful DC 15 Dexterity saving throw to take their actions as normal. If it fails, that creature is stunned until the end of its next turn, panicking and unable to decide what to do. Any creature that remains in the area of effect after the first round is buried by the collapsing ceiling and takes 4d6 bludgeoning damage (if the ceiling is made of earth) or 8d6 bludgeoning damage (if the ceiling is made of stone), plus an extra 2d6 thunder damage regardless of ceiling type. In addition, buried creatures suffer 1 level of exhaustion and are restrained until rescued by another creature; they cannot crawl free on their own. After 2 minutes (for earth) or 1d3 days (for stone), buried creatures run out of oxygen and die (unless they don’t need to breathe, like constructs or undead).

Those not buried but still trapped requires excavation magic like move earth or stone shape, or else a solid day to a week’s worth of digging depending on how much of the ceiling collapsed, and whether it is made of earth (faster) or stone (longer).

Once the trap is triggered, the floor of the area of effect is filled with mounds of soft earth and/or rubble that becomes difficult terrain.

Construction Time: The trap requires advanced engineering and construction techniques. It takes 2 weeks to build from scratch, or 4 weeks to retrofit into an existing location. It requires an engineer or a stonemason, miner, sapper, or similar background. A crew consisting entirely of dwarves, duergar, or deep gnomes reduce the construction time by half. Using earth elementals and/or excavating magic can shorten construction time and costs by half. Combining these time and cost reduction options cannot reduce the trap’s cost below 100 gp for earth or 200 gp for stone.

Cost: 250 gp for earth or 500 gp for stone. Larger areas of effect double the cost.

---

Chute

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

A chute is used to capture and redirect creatures from one area to another, usually to their deaths, imprisonment, or simply out of a restricted area. In some cases, the chute is not a trap at all, but a method to quickly transport defenders or goods to a needed area or to be a means of escape.

Typically, a chute consists of a concealed entrance that opens into a long, narrow shaft at an incline that forces creatures or objects to move down it by gravity.

A chute can be made out of anything from polished stone to wood to metal, depending on the desires and level of resources available to the trap’s creator.

An unconcealed chute is intended solely for the convenience of the creatures residing there, and will be prominently placed in a wall or floor, perhaps with hand grips to make it faster to enter the chute safely if people transport is its primary function. Other functions include coal, food, garbage, laundry, or other supply delivery; these chutes end in a room intended for the use or storage of those goods.

Related Traps: Acid Cauldron, False Staircase, Illusory Floor, Missing Staircase, Pit (Flooded), Pit (Hidden), Teleport Trap.

Trigger: The trap activates when a creature enters it.

Spot: Spotting a chute is requires a successful DC 10 Perception check if unconcealed, or DC 15 if concealed.

Disarm: Disarming this type of trap requires either magical means or physically blocking off the exit point at the bottom so that those who pass through don’t fall into whatever danger awaits them below. Using a spell like wall of force or wall of stone would disarm the chute at the point the spell effect begins, but would result in creatures already sliding with momentum to take 1d6 bludgeoning damage for every 10 feet they’ve traveled before hitting the wall.

Dimensions: The entire length of the chute.

Number of Uses: Limitless.

Reset: Unless its entrance or exit has been sealed off, the chute does not need to be reset. However, if there is some refillable requirement at the end of the chute (acid, lava, monsters, etc.), then those will have to be transported in to reset that portion of the trap.

Effect: Once inside the chute, creatures find themselves knocked prone and sliding down a steep incline at ever-increasing speed toward the bottom.

The chute can lead anywhere—from a simple 10 foot drop onto solid ground, into a pit filled with spikes, into a pool of acid or lava, a prison cell, or monster lair.

Create a destination room or choose another trap type to be destination.

Construction Time: Installing a chute in a building is faster and easier than one that must be tunneled in a dungeon or other underground location. Adding chutes to buildings requires 2 weeks if the building is also new construction. Modifying an existing structure to house a chute is more complicated and doubles installation time to 4 weeks.

Chutes in dungeons or other remote and/or underground locations require 1 week per 30 feet of chute length if created by nonmagical means. These times do not include the time to create and transport the actual chute; add another 2 weeks for wooden chutes, 3 weeks for stone (which must be worked and smoothed), and 4 weeks for metal chutes.

Cost: A wooden chute costs 50 gp per 30 feet. A stone chute costs 100 gp per 30 feet. A metal chute costs 150 gp per 30 feet. These prices include construction of the trigger mechanism as well as the tunnel to house the chute. It does not include the cost of whatever room and/or hazard waits at the chute’s exit.

---

Collapsing Roof

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap uses a tripwire to collapse the supports keeping an unstable section of a ceiling in place. Unlike a cave-in that seals off an entrance or exit, a collapsing roof can be used in any cave, tunnel, room, or corridor. Optionally, it might not be an intentional trap, but the result of an earthquake, thunder damage, etc.

Related Traps: Boulder Drop, Cave-In, Crumbling Ledge, Crushing Walls, Log Jam, Rolling Sphere, Sinkhole.

Trigger: The trap is triggered by any Small or larger creature that touches the tripwire, which is a thin wire strung from one side of the area to the other. It is also triggered if 20 or more points of area effect damage is released in its vicinity, or half that amount for force, lightning, or thunder. Tiny or incorporeal creatures do not activate the trap.

Spot: The tripwire is 3 inches off the ground and stretches between two support beams. A successful DC 10 Perception check reveals the tripwire in bright light, while DC 13 spots it in dim light. DC 15 spots a tripwire in nonmagical darkness or below murky water.

Anyone who inspects the beams can easily determine that they are merely wedged in place. As an action, a character can knock over a beam, causing the trap to trigger.

The ceiling above the tripwire is in bad repair, and anyone who can see it can tell that it’s in danger of collapse.

Disarm: A successful DC 15 Dexterity saving throw using thieves’ tools disables the tripwire harmlessly. A character without thieves’ tools can attempt this check with disadvantage using any edged weapon or edged tool. On a failed check, the trap triggers.

Dimensions: The entire roof of a single cave or room, or a total or partial section of corridor or tunnel.

Number of Uses: One.

Reset: As long as the trap was only disarmed, not triggered, it can be reset in 10 minutes by a single creature with an engineering, mining, sapping, stonemason, or similar background that makes a successful DC 13 Investigation check.

The DC for dwarves, duergar, deep gnomes, and earth elementals to reset this trap is only 11. If their check fails, nothing happens. If anyone else tries to reset it, a successful DC 17 Investigation check is required to do so, and it takes 1 hour. If this check fails, the trap is triggered.

Effect: When the trap is triggered, the unstable ceiling collapses. Any creature in the area beneath the unstable section must succeed on a DC 15 Dexterity saving throw, taking 22 (4d10) bludgeoning damage on a failed save, or half as much damage on a successful one.

Once the trap is triggered, the floor of the area is filled with rubble and becomes difficult terrain.

Construction Time: The trap requires advanced engineering and construction techniques, typically taking at least 4 weeks to build from scratch (or 6 weeks to retrofit into an existing location). It requires an engineer or a stonemason, miner, sapper, or similar background. Using earth excavating magic can shorten construction time and costs by half. Combining these time and cost reduction options cannot reduce the trap’s cost below 200 gp for earth or 250 gp for stone.

Cost: 500 gp for earth or 1,000 gp for stone. Larger areas of effect than standard double the cost.

---

Crushing Walls

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap is designed to trap unsuspecting adventurers in a room or corridor, with two exits that will each be sealed by a falling portcullis at the same time. The trap is triggered by a pressure plate in the center of the room or corridor, which sets off a mechanism that drops the portcullises and begins to slowly close both exits simultaneously. The walls come together to crush any creature or object caught between them.

Related Traps: Boulder Drop, Cave-In, Collapsing Roof, Crushing Walls, Log Jam, Portcullis, Rolling Sphere, Sinkhole.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 15 Perception check reveals the pressure plate, but not its function.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

The trap can also be disabled from outside by activating a well-hidden lever on an exterior wall; a successful DC 17 Investigation check is required to find it. Pulling this stubborn lever requires a character with a 13 or higher Strength score. When pulled down, it reverses the closing mechanism and disarms the trap. When pulled up, it resets the trap.

Dimensions: This trap works best in rooms or corridors 5-feet to 10-feet wide with two separate exits/doors that can be sealed off when triggered.

Number of Uses: One, until reset.

Reset: Automatic (see below). See Disarm above.

Effect: Activation of the trap requires all creatures present to roll initiative. The trap rolls initiative with a +8 bonus. Once triggered, the trap sequence proceeds in the following order:

• Round 1: Both portcullises drop (see Portcullis).
• Round 2: The walls make a grinding noise and the area vibrates as if experiencing a minor earthquake.
• Round 3: The walls begin to perceptibly close slowly but evenly towards each other.
• Rounds 4-7: The walls continue to close, leaving less and less room to maneuver.
• Round 8-10: The walls meet at their halfway point. Any creature caught between them must make a DC 17 Strength saving throw or suffer 10d10 bludgeoning damage per round; success halves the damage. Any object worn or carried by a creature that fails its saving throw that is not relatively flat, thin, or secured by ample padding (such as might be found in a belt pouch or backpack) is crushed and destroyed.
• Rounds 11-18: The walls slowly begin pull back to their original positions as the trap resets itself.
• Rounds 19-20: The portcullises retract back into the ceiling. On round 19, a creature can crawl under them (see Portcullis), and on round 20, creatures can walk under them.

Options

If you’d like to customize this trap, choose from the options below.

Instant Tomb: This version of the trap is designed to stay sealed forever after round 10. It can be disarmed, but has no reset mechanism.

Horizontal Crush: In this version, the walls do not come together, but the ceiling comes down to hit the floor instead. This achieves the same result, and has the added benefit of giving trapped creatures less time to deal with the portcullises, as they lose their leverage faster. Attempts to bend or lift the portcullises made after round 4 suffer disadvantage, and it becomes impossible after round 6.

Construction Time: Constructing this trap usually takes about 8 weeks for new construction or double that to retrofit existing construction. An engineer, blacksmith, and stonemason are required.

Cost: This trap costs 25,000 gp for new construction or double that for existing construction. The horizontal crush option adds an extra 10,000 gp.

---

Disease Dump

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap drops diseased matter down from the ceiling of a room, doorway, or passage. Optionally, it can drop broken glass, garbage, paint (to mark intruders), etc.

Related Traps: Murder Hole, Net Trap.

Trigger: The trap is triggered by any Small or larger creature that touches the tripwire, which is a thin wire strung from one side of the area to the other. Tiny or incorporeal creatures do not activate the trap.

Spot: The tripwire is 3 inches off the ground. A successful DC 10 Perception check reveals the tripwire in bright light, while DC 13 spots it in dim light. DC 15 spots a tripwire in nonmagical darkness or concealed below murky water.

Disarm: A successful DC 15 Dexterity saving throw using thieves’ tools breaks the tripwire harmlessly. A character without thieves’ tools can attempt this check with disadvantage using any edged weapon or edged tool. On a failed check, the trap triggers.

Dimensions: The trap spans the width of a single room, doorway, or passage. The ceiling must have enough clearance to effectively hold and conceal the payload in its container, which might be a waterproof tarp or bucket suspended over the desired point of impact (such as a doorway).

Number of Uses: One, unless refilled and manually reset.

Reset: The area must be cleaned and the trap refilled and rebuilt from scratch; this requires 1 hour for a single creature or half that time for two or more.

Effect: When triggered, the trap releases diseased matter from a container suspended from the ceiling above. This matter could be putrid liquids, bodily fluids, bandages, and/or blood. This material is heavily contaminated with a disease of the GM’s choice. When the trap activates, the diseased matter drops directly on the creature that triggered it. However, aerosolized droplets of disease also spray up and hang in the air around the point of impact for 1 minute. Any creature within a 20 foot radius sphere of the trap must make a Constitution saving throw. Creatures beyond that range do not need to save unless they enter the area of effect before the aerosolized droplets’ 1 minute is up.

Creatures walking through the area of effect for the next 24 hours may track and carry the dis-ease on their footwear unless 1 minute is spent washing them off with soap and water, alcohol, etc.

• Sewer Plague: DC 11
• Cackle Fever: DC 13
• Sight Rot: DC 15

Optionally, you can choose a different disease. Other ideas include magical diseases like lycanthropy or vampirism.

Options

If you’d like to customize this trap, choose from the options below.

Blight Spores: Any creature caught in the trap’s area of effect must succeed on a DC 15 Constitution saving throw. If it fails, it takes 4d6+4 necrotic damage and suffers the poisoned condition. Every round after it has left the trap’s area of effect, the creature is allowed a new saving throw to negate the condition. If the saving throw succeeds, the creature takes half damage and is not poisoned.

Broken Glass: This version replaces the diseased material with broken glass. Any creature that fails a DC 10 Dexterity saving throw gets itchy shards of broken glass inside its clothing or armor that cuts them for 1 point of slashing damage. Until the creature spends 1 minute to strip out of its clothes and/or armor to remove the broken glass, it continues to take 1 extra point of slashing damage every time it moves faster than half-speed or whenever it takes damage from any other source. This effect cannot reduce a creature below 1 hit point; if it would, ignore all further damage from this effect until the creature has been healed to 2 hit points or more.

Fungal Spores: In addition to the normal disease, any creature affected by this trap must succeed on an additional DC 12 Constitution save or be infected with spores that cause red, itchy fungal rot. The rot appears after the creature completes a long rest. After that, the rot deals 1 point of necrotic damage per day and reduces an infected creature’s speed by half. It also gives it disadvantage on attack rolls, skill checks, and saving throws until cured.

Garbage: This version replaces the diseased material with a bucket of rotten eggs, food, and other harmless garbage (GM’s choice). Any creature that fails a DC 10 Dexterity saving throw is hit by the bucket for 1d2 bludgeoning damage and covered in stinking garbage. If the saving throw fails by 5 or more, the creature is blinded by the garbage until it spends 1 action to clear it from its eyes. In addition, any rolls to track or perceive a creature covered in garbage are made with advantage by creatures that can smell. This stink persists until the creature’s clothes and/or armor are cleaned or replaced.

Creatures adjacent to (and within 5 feet) of the creature that triggered this trap must also make a saving throw or be covered in garbage, but they cannot be blinded by it.

Necrotic Slime: In addition to the normal disease, any creature affected by this trap takes an extra 1d6 necrotic damage and is poisoned until it completes a long rest.

Poisonous Slime: In addition to the normal disease, any creature affected by this trap takes an extra 1d6 poison damage and is poisoned until it completes a long rest.

Sympathetic Magic: If a diseased or spores version is used, all necromancy magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 necrotic damage on a failed save regardless of whether it normally deals necrotic damage or not.

Wet Paint: This version replaces the diseased material with a bucket of brightly colored paint (GM’s choice of color). Any creature that fails a DC 10 Dexterity saving throw is hit by the bucket for 1d2 bludgeoning damage and covered in paint. If the saving throw fails by 5 or more, the creature is blinded by the paint until it spends 1 minute washing the paint out its eyes. In addition, any rolls to track a creature covered in paint are made with advantage for the next 10 minutes unless the paint is magically removed.

Creatures adjacent to (and within 5 feet) of the creature that triggered this trap must also make a saving throw or be covered in paint but they cannot be blinded by it.

Construction Time: Constructing this trap usually takes about 2 hours, not counting time spent gathering and assembling the diseased matter or other desired components. It requires a rope and pulley system, wire, two iron spikes to tie the wire to, and a waterproof tarp, bucket, or other container. Optionally, a bucket could be placed over a slightly open doorway, easily tipped over when the door is fully opened. This version only takes 10 minutes to construct.

Cost: This tripwire version of this trap costs 10 gp plus any additional for poison, spores, etc. The bucket over the door version costs practically nothing (the cost of the bucket plus any extras).

---

Drawbridge

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap is often used to keep an entrance secure from intruders, but it can also be used to prevent creatures from escaping. While in motion, it also presents a challenging terrain for fight or flight. A drawbridge is always placed over a ditch, moat, or pit and paired with a portcullis as an additional security feature. The bridge is wood or metal, and it is operated by ropes or chains from a fortified gatehouse overhead. (A metal drawbridge is always operated by chains.)

Related Traps: Ditch, Moat, Murder Hole, Portcullis, Spiral Staircase.

Trigger: Most drawbridges are triggered manually by the location’s defenders or by those trying to escape after overpowering the guards and drawbridge operators. However, some drawbridges are magical and operate automatically for authorized creatures who wear a coded badge or medallion, or who speak the command word.

Spot: No check is necessary to spot a drawbridge, but a DC 10 Perception check can be made to detect when it is about to be activated by creatures on the drawbridge or within 60 feet of it who are not deafened.

Disarm: The mechanism that operates the drawbridge can be jammed and/or its ropes cut, or chains broken. See Destroy, below.

Dimensions: A typical castle or city drawbridge is between 20 feet tall/long and 20 feet wide to accommodate carriages, wagons, and 2 side by side horses (with riders). Other drawbridges may be taller, shorter, or narrower depending on their use.

Number of Uses: One, until reset.

Reset: A team of two creatures with 13 Strength or better is required to operate the drawbridge unless it is powered by magic. Regardless of whether it is a manual or automatic (magic) reset, the drawbridge can be lowered in 3 rounds, or raised in 5.

Effect: Activation of the trap requires all creatures present to roll initiative. The drawbridge rolls initiative with a +8 bonus. When triggered, the drawbridge begins to raise or lower according to whether it is already up or down. If creatures are being admitted, the portcullis is also raised or kept up. If creatures are leaving, the portcullis usually raises 1 round before they begin to exit and closes 1 round after the last of them exits the drawbridge.

Creatures on the drawbridge while it is being raised or lowered treat the drawbridge as difficult terrain and must make a Dexterity saving throw to avoid falling off (or back down it) each round until it closes.

A creature who falls off it takes falling damage (unless it falls into a moat). A creature that falls down the drawbridge tumbles back inside the location; it takes appropriate falling damage and is knocked prone.

• Round 1: DC 10 Dexterity saving throw. Mounted riders can make a DC 10 Animal Handling check if they prefer.
• Round 2: The Dexterity save (or Animal Handling check) increases to DC 13.
• Round 3: The Dexterity save (or Animal Handling check) increases to DC 17.
• Round 4: The Dexterity save (or Animal Handling check) increases to DC 19.
• Round 5: The Dexterity save (or Animal Handling check) increases to DC 21. You must exit the drawbridge to either side by the end of this round or take falling damage.

On rounds 1-2, while the drawbridge is being raised and you are within 10 feet of the top of it fighting creatures below you, you gain a +1 bonus to attack rolls. The creatures below you suffer a -1 penalty to attack rolls made against you.

This dynamic changes on rounds 3-5 when you must fight to keep your footing. You lose the attack roll bonus the drawbridge previously gave and now suffer disadvantage on your attack rolls, saving throws, and skill checks. The creatures below you lose their previous penalty and instead gain advantage on attack rolls against you.

DESTRUCTION

The drawbridge is raised or lowered via either ropes or chains. The ropes are thick and have 30 hit points each. Its chains are also thick, but have 60 hit points. Both are greased to allow easier movement, and this makes them resistant to slashing damage, but this makes the rope version vulnerable to fire damage. The chains are immune to fire damage. Cutting the ropes or breaking the chains force the drawbridge to drop and it remains that way until it is repaired.

The gears and other moving parts inside the gatehouse that operates the drawbridge from above have a combined total of 120 hit points, but become jammed if a sturdy object (such as creature or sword) is wedged between them. Once the jam is removed, the drawbridge becomes operational again.

Construction Time: Constructing this trap takes 1 month for new construction or double that amount to retrofit existing construction. An engineer, stonemason, and woodworker are required.

Cost: 250 gp if using ropes to raise or lower a wooden drawbridge, 350 if using chains for a wooden drawbridge, or 500 gp if using chains on a metal drawbridge.

---

False Door

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap consists of what appears to be a normal (or special) door, either made of wood or metal.

Related Traps: Ballista Corridor, Electrocution Door, False Staircase, Guillotine Door, Wall of Spears.

Trigger: The trap activates when the door is opened.

Spot: There is no obvious giveaway that reveals this trap. As a cost-cutting ore time-saving measure, sometimes false doors do not match the overall look or feel of the normal doors at the location; if this is the case, then a successful DC 13 Perception check reveals that fact.

Disarm: There is no way to disarm the trap.

Dimensions: One door of any size.

Number of Uses: One, until reset.

Reset: The trap must be reset manually, requiring 1 minute.

Effect: When the door is opened, a wood or stone wall is revealed instead of a room. There is a hole in the wall placed at abdomen level for Medium creatures or head-level for Small creatures. Hidden behind this wall is a spring-loaded, barbed iron spear. It is built into the machinery that operates it, which forces it to shoot out to half its length.

The creature that opened the door must make a DC 15 Dexterity saving throw. On a success, it takes 1d8 piercing damage as it is gashed by the spear. On a failure, it takes 2d8 piercing damage and is impaled and restrained until freed by another creature. The impaled creature takes an extra 1d8 piercing damage when it is freed from the barbed spear.

In addition, a creature standing directly behind and adjacent to the impaled creature must succeed at a DC 13 Dexterity saving throw or take 1d4 piercing damage as the spearhead emerges from the creature that triggered the trap to strike into them as well. This creature is not impaled or restrained if it fails its saving throw.

Options

To customize this trap, choose from the options below.

Flying Spear: Some versions of this trap are rigged with reloadable ammunition. These traps cause the loaded half-spear to be loosed at high velocity with a range of 20/60. Every creature of Small size or larger in its flight path must succeed at a DC 15 Dexterity saving throw to avoid being struck by it. On a failed save, the creature takes 2d8 piercing damage and is impaled (but not restrained). The impact stops the half-spear so it does not threaten any creatures behind the one struck.

Multiple Spears: Some versions of this trap include up to three spears arranged at different heights. Each additional spear adds an extra 1d8 piercing damage on a successful save, or 2d8 on a failed save. Use logic to determine whether the extra spears would actually hit a creature of a certain size, as these traps are typically built to target Medium creatures.

Trap-Free: Some false doors are precisely that—false doors—and do not include a trap component. These are typically placed as part of another trap, to lure intruders into thinking they have a viable exit or escape route where none exists. This type of door may or may not be capable of opening, but can be destroyed or taken down from its frame by removing the hinges.

Trident Swap: If desired, you could replace the iron half-spear with a different or more thematic piercing weapon, such as a trident for an aquatic-themed lair.

Construction Time: This trap requires one day to install, assuming the trap mechanism, spear, and door already exist on site. Otherwise, add a week or two to the construction time. It requires an engineer, blacksmith, and stonemason to built this trap.

Cost: 250 gp including the spear trap, or 25 gp if the door only leads to a blank wall instead.

---

False Staircase

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap consists of a false staircase, better known as a “staircase to nowhere.” It is usually narrow (5 foot wide), often spiral in design (see Spiral Stairs), and frequently combined with an ankle biter, chute, false door, illusory floor, pit trap, portcullis, or wall of spears. These additional traps usually appear on the false staircase itself or at or near where it terminates.

Related Traps: Ankle Biter, Chute, False Door, Illusory Floor, Missing Staircase, Portcullis, Spiral Staircase, Wall of Spears.

Trigger: The trap is triggered when any creature reaches either the end of the staircase or a certain strategic point on it (if it is paired with another trap).

Spot: If the staircase is straight and ends abruptly at the base, a DC 10 Perception check in bright light reveals that fact, or DC 12 in dim light. If it is a spiral staircase, and the top or bottom is not visible while you are climbing it, then there is no way to know how it ends until you get at or near the end. As a cost-cutting measure, sometimes false stair-cases do not match the overall look or feel of the normal staircases at the location; if this is the case, then a successful DC 13 Perception check reveals that fact.

Dimensions: The entire length and width of the staircase.

Number of Uses: Limitless, unless destroyed or sealed off.

Reset: N/A

Effect: The staircase either abruptly terminates at a dead end or pit, or leads to a dead end passage, or the stairs suddenly flatten to become a chute.

Options

To customize this trap, choose from the options below.

Pit Trap Stairs: Some versions of this trap feature a Pit (Hidden) at the halfway point. It has the locking feature, so a creature who fell in would “disappear” and the stairs would appear as normal once the pit closed and locked. Pit Trap Stairs usually have spikes in the bottom, or maybe a hungry, half-starved ghoul…

Sliding Stairs: Some versions of this trap are triggered by a pressure plate at about the halfway point (DC 15 Perception to spot). This turns the entire staircase into a chute (see Chute). A Pit (Hidden) and/or Acid Cauldron usually wait at the end.

Construction Time: It takes a week per 10-foot section to excavate and fashion a stone staircase, plus an additional week if the steps are to be finished properly and made to match the aesthetics of other stair-cases in the facility. For wooden stairs, this time is halved. Stone staircases require a stonemason; wooden staircases require a woodworker.

Cost: 50 gp per 10-foot long, 5-foot wide section of stone staircase, or double that cost to make it 10-foot wide. All costs for a wooden staircase are halved unless expensive, imported wood is used.

---

Fire Walk (Difficult Terrain/Mechanical Trap)

Source Game Master’s Guide to Traps & Terrors

This area combines difficult terrain (hot coals) with multiple pit traps. It is most often found in a shrine or temple to a fire god, forge god, sun god, or devil warlock patron. It is used as a trap, but can also be used in a ceremonial context as a traditional fire walk and “show of faith”.

A large but shallow fire pit (more of a ditch) is visible in the middle of a 15-foot wide room or corridor. It is alight with burning coals and sheds bright fiery light in 20 foot radius and dim fiery light for an additional 20 feet. The pit is 5-feet wide by 60- feet long, but only 2-feet deep. Along each side of the fire pit is a narrow 5-foot tiled walkway inlaid with strange golden symbols, and painted with grotesque murals depicting sacrifices to various fire creatures.

The symbols on the floor do not repeat in any particular order. They may be written in an unknown or dead language, secret code, Abyssal, Infernal, or Primordial (Ignan). If they can be read, they roughly translate as, “Come forward in flame or go down in despair.” Related Traps: Lava Doom, Magic Landmine, Pit (Hidden), Wall of Fire.

Trigger: The trap is activated when a creature attempts to cross the area and comes in contact with the coals and/or pressure plates. pressure plates require 20 pounds or more of pressure to be applied to activate. Tiny or incorporeal creatures do not activate the trap. Regardless of pressure, the coals instantly trigger their effect as soon as they are touched.

Spot: A successful DC 15 Perception check reveals the pressure plates that trigger the pit traps along the sides.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered. If you use the optional center pit trap, there is no way to detect it short of magic like find traps or clearing away the burning coals.

Dimensions: One 60-foot long, 15-foot wide stone corridor or room, plus the space allotted to house the pit traps underneath.

Number of Uses: Limitless, provided you have replacement coal or magic to sustain the existing load’s temperature.

Reset: The hot coals must be kept perpetually hot by magic or mechanical means, or periodically cleaned out and replaced. Otherwise, they stay hot for the first 12 hours and deal half damage for the next 12 hours before going cold.

Effect (Difficult Terrain): You move at half-speed in this difficult terrain as its intense heat and narrow walkways make moving faster dangerous.

Effect (Hot Coals): The coals deal 1d4+1 fire damage each round to any creature that attempts to move across them faster than half speed (no save).

Due to the uneven, shifting texture of the coals, any creature moving at full speed or taking the Dash action will take 2 rounds to reach the other side. In addition, it must make a DC 15 Dexterity saving throw when halfway across or slip and be knocked prone into the coals. This deals 1d8+2 fire damage that round instead of the usual 1d4+1.

Creatures moving at half speed take 1d2 fire damage (DC 13 Dexterity saving throw for half damage, minimum 0) and require 3 rounds to cross the coals. Creatures moving slower than that take no damage and require 6 rounds to cross. Those moving at half speed or less do not need to make saving throws to maintain their balance.

Effect (Pit Trap): Every 10 feet on the left hand path, there is a hidden pit trap. Creatures that use the left walkway must make a DC 12 Dexterity saving throw or fall into a 5-foot wide, 10-foot deep spiked pit also filled with burning coals. This deals 1d6 bludgeoning damage from the fall, plus 1d6 piercing damage from the spikes, and an extra 1d4+1 fire damage from the coals. Every 15 feet on the right hand path, there is a hidden pit trap. Creatures that use the right walkway must make a DC 15 Dexterity saving throw or fall into a 5-foot wide, 10-foot deep spiked pit also filled with burning coals. This deals 1d6 bludgeoning damage from the fall, plus 1d6 piercing damage from the spikes, and an extra 1d4+1 fire damage from the coals. A creature that fails its save by 5 or less can, if they wish, attempt to grab onto the rim of the fire pit to try to pull themselves up before they fall to the bottom. It requires a successful DC 13 Athletics or Acrobatics check to pull themselves up, but they are knocked prone.

Options

To customize this trap, choose from the options below.

Central Fire Pit: In this version of the trap, there is a secret 10 by 10 foot pit halfway across the fire pit. This pit cannot be seen since it is covered by coals. This drops into a 30-foot deep pit lined with spikes and hot coals. Creatures are allowed to make a DC 15 Dexterity saving throw to avoid the pit. A successful save allows them to land on the side of the pit they prefer. An unsuccessful save drops them into the pit and deals 3d6 bludgeoning damage from the fall, plus 3d6 piercing damage from the spikes, and an extra 1d4+1 fire damage from the coals. A creature that fails its save by 5 or less can, if they wish, attempt to grab onto the rim of the fire pit to try to pull themselves up before they fall to the bottom. It requires a successful DC 13 Athletics or Acrobatics check to pull itself up, but it is knocked prone and now on hot coals. This deals 1d8+2 fire damage that round instead of the usual 1d4+1.

Fire Pit Creatures: The pits can open into small 10 by 10 foot prison cells that each contain a fire elemental, fire-related fiend, or other fire-related or immune monster of an appropriate CR for the party. In this case, the spikes would only cover the 5 foot area directly under the pit trap, but the coals would cover the entire floor, to give the creature room to live/move without interacting with the spikes.

Fireball (1/day): If the trap is desecrated by the party in any way (including cooling or removing its coals), it casts fireball centered on the creature responsible for the most desecration. This deals 8d6 fire damage.

Hellish Rebuke (1/round): If the trap is blasphemed or desecrated by the party in any way (including cooling or removing its coals), it casts hellish rebuke on the creature responsible for the most desecration that round. This deals 2d10 fire damage.

Summon Extraplanar Guardians (1/Day): If the trap is desecrated in any way by the party (including cooling or removing its coals), the trap summons two fire-related elementals or fiends of CR 3-5, or five of the same creature type of CR 2 or less. The called creatures arrive by a mystic gate within 30 feet of the trap in 1 round and attack all unauthorized creatures present, remaining and/or pursuing them until defeated or destroyed, or until 1 hour passes.

Sympathetic Magic: All Fire and Cloud magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 fire damage on a failed save regardless of whether it normally deals fire damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap takes 12 weeks. It requires an engineer and stonemason. An arcane or divine caster is required to create a permanent, magically hot version. Continual flame is often added; if it is, the trap radiates evocation magic.

Cost: 1,000 gp for the mechanical version or 3,000 gp for a magical version with always hot coals (with or without continual flame added). The cost of acquiring optional fire creatures isn’t included and up to the GM.

---

Flood Zone

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap is designed to trap unsuspecting adventurers in a room or corridor, with two exits that will each be sealed by a falling blast door (see Portcullis) at the same time. The sealed area begins to slowly flood to ceiling level through water or another liquid of the GM’s choice poured through a series of iron grilles (see Portcullis). The grilles are set at waist-height that run along both walls with an equal number of additional grilles set along the floor at even intervals.

Related Traps: Acid Cauldron, Murder Hole, Quicksand, Quickslime, Quicklime Geyser, Steam Geyser.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 15 Perception check reveals the pressure plate, but not its function. The metal grilles, on the other hand, are easy to spot and don’t require a check. If a bright light is used to look inside, a small stone or metal chute is seen.

The chute ascends upwards in the waist-high ones and downward in the floor-level ones, but the end cannot be seen in either even if the grille is removed.

The grilles are Small, but if removed and explored, the chutes behind them rapidly narrow to Tiny. The waist-high ones lead to the water or other liquid source. The floor grilles are the same dimensions, but lead down and to wherever the water or other liquid is drained and/or recycled.

Discerning the grilles’ function as a delivery mechanism requires a DC 15 Investigation check; on a failure, they “might be air vents” is the best that can be surmised. However if anything other than fresh or stagnant water is used to flood the area, such as acid, salt water, sewage, slime, or another pungent liquid, then regardless of the check’s success or failure, that smell will be noted as coming from behind the grilles.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

The trap can also be disabled from outside by activating a remarkably well-hidden lever on an exterior wall; a successful DC 17 Investigation check is required to find it. Pulling this stubborn lever requires a character with a 13 or higher Strength score. When pulled down, it reverses the closing mechanism and disarms the trap. When pulled up, it resets the trap.

Dimensions: This trap works best in rooms or corridors 5 feet to 10 feet wide with two separate exits/doors that can be sealed off when triggered.

Number of Uses: One, until reset.

Reset: Automatic (see below). See also Disarm, above.

Effect: Activation of the trap requires all creatures present to roll initiative. The trap rolls initiative with a +8 bonus. Once triggered, the trap sequence proceeds in the following order:

• Round 1: Both blast doors drop (see Portcullis).
• Round 2: The sound of running water (or other liquid) comes from behind the grilles (see Portcullis).
• Round 3-5: Water (or another liquid of the GM’s choice) pours through the grilles and begins to flood the area. If the liquid deals damage, it begins to do that now, but creatures gain advantage on saving throws against it during these 3 rounds.

Creatures may also move freely during this time.

• Rounds 6-8: The water (or other liquid) continues to fill the area and now reaches knee-high. Speed is reduced by half. If the liquid deals damage, creatures no longer receive advantage on saving throws against it.
• Rounds 9-11: The water (or other liquid) reaches waist-high. Speed is reduced to one-quarter. If the liquid deals damage, creatures suffer disadvantage on saving throws against it from this point on.
• Rounds 12-14: The water (or other liquid) reaches chest-high. Speed is reduced to 5 feet per round unless they have a swim speed and/or choose to swim.
• Rounds 15-18: The water (or other liquid) reaches neck-high.

 

Creatures are restrained (treading water) unless they have a swim speed and/or choose to swim.

• Rounds 19-20: The water (or other liquid) reaches within a few inches of the ceiling. Creatures are restrained (treading water) unless they have a swim speed and/or choose to swim.
• For the next hour, the water reaches and remains at ceiling-height. Any living creature that requires air to breathe drowns and is dead after 2 minutes.
• After that hour, the water or other liquid drains out over 10 minutes. After that, the blast doors slowly retract back into the ceiling. On the first round they retract, a creature can crawl under them (see Portcullis), and on the following round, it can walk under them.

 

Options

To customize this trap, choose from the options below.

Boiling Water: The trap uses boiling water to deal an extra 2d6 fire damage per round to any creature exposed to it; a successful DC 13 Dexterity saving throw reduces the fire damage by half. In addition, the area quickly becomes heavily obscured due to steam.

Dirty Water: The water in the trap is contaminated, such as with raw sewage, parasites, and/or decomposing bodies. A creature who falls in or otherwise comes into contact with the water must make a DC 11 Constitution or Dexterity saving throw (whichever score is higher) or be poisoned for a number of hours equal to 10 – its CON modifier (if positive). If the GM wishes, the water can also be diseased.

Instant Tomb: This version of the trap is designed to stay sealed after round 1. It can be disarmed, but has no reset mechanism.

Paralyzing Slime: The trap exudes paralyzing slime instead of water. A creature attempting to enter, move through, or escape the coated area at the start of its turn must make a DC 14 Constitution saving throw or be paralyzed for 1 minute. If it fails, it is also knocked prone by a sudden wave of nausea causing it to slip in the slime. Creatures in heavy armor save against this with advantage. A paralyzed creature can make a new save each round to negate the condition.

Paralyzed prone creatures will drown in the slime.

Construction Time: Constructing this trap takes 8 weeks for new construction or double that to retrofit existing construction. An engineer, blacksmith, and stonemason are required.

Cost: This trap costs 10,000 gp for new construction or double that to retrofit existing construction.

---

Foot Trap

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

The foot trap is also commonly known as an animal trap or hunter’s trap. It is the classic metal “mouse trap” design, but scaled up to be effective against Small to Large size creatures. Its primary targets are poachers and trespassers, or predatory beasts or wild game.

The trap may or may not be chained to a tree or bolted to a floor, but it is usually concealed under debris, dirt, foliage, or water. Depending on whether the trap is stepped on or fallen on determines which body part the trap’s jaws snap shut around.

Related Traps: Ankle Biter, Magic Landmine, Man-Trap, Net Trap, Pit Trap (Simple), Swinging Death.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate located between the metal jaws in the center of the trap. It may also be activated by removing bait from the pressure plate. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 10 Perception check spots an unconcealed trap in bright light, while DC 13 spots an unconcealed trap in dim light or a concealed trap above ground or in shallow or clear water. DC 17 spots a trap in nonmagical darkness or concealed below murky water. If the trap is baited to lure prey, then the DC to spot it is reduced by 2.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

Dimensions: Varies by size category of the intended target, but the trap always fits within a 5 foot square.

Number of Uses: One, until reset.

Reset: A creature with 13 or higher Strength can manually reset the trap in 1 minute by prying open its jaws and locking them back into place, then baiting or concealing the trap.

Effect: When triggered, the metal jaws snap shut around the target creature’s leg, inflicting 1d4+1 bludgeoning and 1d4+1 slashing damage if it is a Tiny to Large creature.

The target is also restrained if the trap is secured to a tree or bolted to the floor. It can only move as far as the length of chain allows, typically no more than 5-10 feet in any direction, and then only 5 feet per round within that range. If the trap is unsecured, the target is not restrained, but its speed is reduced by half. Even after the trap is removed, the penalty to speed remains until the injured limb is magically healed or the creature finishes a long rest. If the trap was fallen on instead of stepped on, its jaws may snap shut on one of the following body parts instead of just the leg (choose or roll 1d10): If the head/neck or chest/torso is indicated, the damage is an automatic critical hit. If an arm is indicated, there is no penalty to speed, but that arm is useless until magically healed or the target finishes a long rest. Leg results are the same as above.

Huge creatures may trigger the trap, but only take 1 point of bludgeoning and 1 point of piercing damage. They are not damaged, restrained, or slowed by it. Gargantuan creatures may also trigger the trap, but take no damage or other effects from it.

Options

If you’d like to customize this trap, choose from the options below.

Bleeder: The wounds caused by this trap continue to bleed. On each round after the initial injury occurred, the wounded creature continues to lose 1 hit point per round until it or another creature spends an action to bind the wound(s) caused by the trap. Magic healing also ends this effect. While bleeding, the wounded creature leaves a trail of blood behind it that grants advantage to all rolls made to track it.

Diseased Foot Trap: The jaws have not been cleaned of the gore from previous victims. A creature hit by them must make a DC 11 Constitution saving throw or be infected with sewer plague.

Poison Foot Trap: The jaws have been recently coated with poison. This deals an extra 1d6 poison damage; a successful DC 13 Constitution saving throw reduces the damage by half. The GM is free to use a different poison.

Rusty Foot Trap: The rusty jaws deal an extra 1d6 necrotic damage. A successful DC 13 Constitution saving throw reduces the damage by half.

Construction Time: Approximately 1 week. This requires a blacksmith.

Cost: 5 gp if designed for Tiny-Small creatures, 10 gp for Medium, or 20 gp for Large.

d10	Body Part
1-2	Head/Neck
3-4	Left Arm (50%) or Right Arm (50%)
5-6	Left Leg (50%) or Right Leg (50%)
7-8	Torso
9-10	Chest

---

Gas Chamber

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap is designed to trap unsuspecting intruders in a room or corridor, with two exits that will each be sealed by a falling blast door (see Portcullis) at the same time. The sealed area begins to slowly fill with gas, smoke, spores, or steam blown in through a series of iron grilles (see Portcullis) set in the ceiling at even intervals.

Related Traps: Portcullis, Pressed Flower, Wall of Petrifying Poison Gas.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 15 Perception check reveals the pressure plate, but not its function. The metal grilles, on the other hand, are easy to spot and don’t require a check. If a bright light is used to look inside, a small stone or metal chute is seen. The chute ascends upwards, but the end cannot be seen even if the grille is removed.

The grilles are Small, but if removed and explored, the chutes behind them rapidly narrow to Tiny. They lead to an overhead chamber containing gas canisters or another delivery mechanism of the GM’s choice.

Discerning the grilles’ function as a delivery mechanism requires a DC 15 Investigation check; on a failure, they “might be air vents.” However if anything other than fresh or stagnant water is used to flood the area, such as acid, salt water, sewage, or some other pungent liquid, then regardless of the check’s success or failure, that smell will be noted as coming from behind the grilles.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

The trap can also be disabled from outside by activating a remarkably well-hidden lever on an exterior wall; a successful DC 17 Investigation check is required to find it. Pulling this stubborn lever requires a character with a 13 or higher Strength score. When pulled down, it reverses the closing mechanism and disarms the trap. When pulled up, it resets the trap.

Dimensions: This trap works best in rooms or corridors 5-feet to 10-feet wide with two separate exits/doors that can be sealed off when triggered. This allows them to fill with gas more quickly.

Number of Uses: One, until reset.

Reset: Automatic (see below). See also Disarm, above.

Effect: Activation of the trap requires all creatures present to roll initiative. The trap rolls initiative with a +8 bonus. The trap sequence proceeds in the following order:

• Round 1: Both blast doors drop (see Portcullis).
• Round 2: The sound of hissing air comes from behind the grilles.
• Round 3-5: Gas (or another airborne substance of the GM’s choice) pours through the grilles and begins to flood the area. If the substance deals damage or another effect, it begins to do that now, but creatures who require air to breathe and that cover their nose and mouth gain advantage on their saving throws during these 3 rounds.
• Rounds 6-9: The gas (or other substance) continues to fill the area, which is now lightly obscured. Creatures no longer receive advantage on saving throws against it.
• Rounds 10+: Creatures suffer disadvantage on saving throws against the gas (or other substance) during this time. The area is now heavily obscured.
• For the next hour, the gas (or other substance) remains. Any living creature that requires air to breathe suffocates and is dead after 2 minutes.
• After that hour, the floor grilles open and the gas (or other substance) is sucked out of the area through them over the next 10 minutes.
• After that, the blast doors slowly retract back into the ceiling. On the first round they retract, a creature can crawl under them (see Portcullis), and on the following round, creatures can walk under them.

Options

To customize this trap, choose from the options below.

For example, this trap is often paired with stackable effects like Blight Spores, Fey Spores, Fiend Spores, Fumes, Poison Gas, Shadow Spores, Smoke, or Steam Spray.

Confusion Gas: Any creature caught in the trap’s area of effect must succeed on a DC 15 Wisdom saving throw. If it fails, it is affected as if by a confusion spell. If it succeeds, it is unaffected by the gas.

Instant Tomb: This version of the trap is designed to stay sealed after round 1. It can be disarmed, but has no reset mechanism.

Paralysis Gas: Any creature caught in the trap’s area of effect must succeed on a DC 15 Constitution saving throw. If it fails, it suffers the paralyzed condition. Every round after that, the creature is allowed a new saving throw to negate the condition but is considered poisoned on the round the paralyzed effect is negated. If the saving throw succeeds, the creature is poisoned for 1 round but is not paralyzed.

Sympathetic Magic: All Cloud and Poison magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 poison damage on a failed save regardless of whether it normally deals poison damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap usually takes about 8 weeks for new construction or double that to retrofit existing construction. An engineer, blacksmith, and stonemason are required.

Cost: This trap costs 10,000 gp for new construction or double that for existing construction.

---

Guillotine Door

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap appears as a standard sized door with no visible signs of danger, but when opened, it is actually equipped with a hidden guillotine blade trap.

Related Traps: Ballista Corridor, Disease Dump, Electrocution Door, False Door.

Trigger: The trap is activated when the door is opened.

Spot: A successful DC 15 Perception check reveals the frame around the doorway appears to be slightly overbuilt compared to similar doors found in this location. DC 17 if the overhang is concealed as a bas-relief or other ornamental wood or stone work.

Disarm: There is no way to disarm this trap, but it is easy to spring without danger by simply opening the door but not moving through it.

Dimensions: The trap has an area of effect covering the whole doorway. The door opens inward. The trap’s guillotine blade is razor sharp, crafted from solid steel, and once dropped, fills the bottom half of the doorway.

This makes it difficult to enter the room; a creature attempting to climb over the guillotine blade must use all of its movement that turn and loses its reaction that round.

Number of Uses: One, unless reset.

Reset: The trap must be manually reset via a rope or chain pulley system hidden inside the interior wall of the room next to the door. This wall panel can be found and accessed with a successful DC 15 Investigation check. Resetting the trap requires 1 minute for a creature with less than a 13 Strength score to haul the blade up, or half that time for a creature with greater Strength.

Effect: The trap’s guillotine blade slams down from its hidden housing in the frame above. The first creature moving through the doorway after it is opened must make a successful DC 15 Dexterity saving throw or take 4d10 slashing damage. On a failure, the creature is also shoved backwards 5 feet from the door, knocked prone, and stunned. A creature that successfully saves against this effect takes half damage and is shoved 5 feet forward instead, but is not knocked prone or stunned.

Options

If you’d like to customize this trap, choose from the options below.

Bleeder: The wounds caused by this trap continue to bleed. On each round after the initial injury occurred, the wounded creature continues to lose 1 hit point per round until it or another creature spend an action to bind the wound(s) caused by the trap. Magic healing also ends this effect. While bleeding, the wounded creature leaves a trail of blood behind it that grants advantage to all rolls made to track it.

Diseased Blade: The blade has not been cleaned of the gore from its previous victims. A creature hit by it must make a DC 11 Constitution saving throw or be infected with sewer plague.

Living Blade: The trap is a construct that resets itself automatically. Because it can time its attack perfectly, the saving throw DC is increased to 17. In addition, the trap can relentlessly blare and repeat preprogrammed magic mouth alarm, such as “Fresh meat!” but cannot otherwise communicate. A living blade has AC 14 (natural armor) and 20 hit points. It cannot move outside its appointed doorway or up/ down trajectory. The trap radiates illusion magic when this option is added.

Poison Blade: The blade has been recently poisoned.

It deals an extra 2d6 poison damage; a successful DC 13 Constitution saving throw reduces the damage by half. The GM is free to use a different poison if desired.

Rusty Blade: The blade is rusty and deals an extra 1d6 necrotic damage. A successful DC 13 Constitution saving throw reduces the damage by half.

Construction Time: Constructing this trap usually takes about 2 weeks. It requires an engineer, blacksmith, weaponsmith, and woodworker.

Cost: 500 gp + any poison costs. The living blade variant costs 2,000 gp and requires an engineer, wizard, or other appropriate arcane caster capable of casting magic mouth.

Lava Doom

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap is designed to burn creatures to death by separating them and filling the room with hot lava.

Related Traps: Fire Walk, Pit (Hidden), Wall of Fire.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap. The plate is typically located at the midway point between the room’s entrance and exit. It may be also be located near a point of interest, such as an altar, idol, or obvious treasure (which might be cursed or a forgery).

Spot: A successful DC 15 Perception check reveals a series of hairline cracks in the stone floor. These cracks may be symmetrical or puzzle-shaped, as the GM prefers. There are also a series of regularly spaced holes in the ceiling; these may be hard to notice if they are disguised in raised ornamental stonework such as bas-reliefs or gargoyle mouths. If they are concealed, the DC is 17 to realize the holes appear far deeper than the rest of the roof’s ceiling and thus may be more than decorative. The jets inside cannot be seen.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

Dimensions: The trap is the size of an entire room, typically one of the largest in the location. The minimum size is 30 feet tall, 30 feet long, and 30 feet wide, but most will be two or three times that size.

Number of Uses: Once per long rest.

Reset: The trap requires a full 8 hours after being triggered to fully drain and recycle the lava. Until it has fully reset, it remains dangerous to move through, even though the lava jets are no longer active.

Effect: Activation of the trap requires all creatures present to roll initiative. The trap rolls initiative with a +8 bonus.

• On round 1, three enormous grilles of solid steel drop from the ceiling, blocking passage through the room and trapping anyone already in it. The first grille seals the entrance, the second the exit, and the third and final grille split the room in half.

Any character adjacent to a grille when it drops must make a DC 11 Dexterity saving throw to avoid being crushed and restrained for 4d10 bludgeoning damage. If the save succeeds, that creature must decide which side of the grille it wants to be on.

• Round 2 after the grilles come down, there is a harsh stone grinding sound and the entire floor begins to shake violently as if undergoing an earthquake. Anyone attempting to move on this round or any round after it must make a DC 13 Dexterity saving throw or be knocked prone by the powerful vibrations.
• On round 3, portions of the floor begin to sink, 1d3 10-foot squares at a time (determined randomly) in each of the two sections split by the middle grille. They sink 10 feet below the room’s normal floor level, revealing glowing red-orange gaps at their base. The temperature in the room immediately rises 10 degrees and the smell of burning magma fills the area.
• On round 4, lava oozes into the sunken squares.

 

This deals 10d6 fire damage to any creature that comes into contact with it, or half damage with a successful DC 15 Dexterity saving throw. The level rises 5 feet every round until it reaches floor level. This deals 10d6 fire damage to any creature that comes into contact with it, or half damage with a successful DC 15 Dexterity saving throw.

• On round 5, another 1d3 random 10-foot squares of the floor begin to sink in each of the two sections split by the middle grille. They sink 10 feet below the room’s normal floor level, revealing a glowing red-orange gap at their base.
• At the end of round 5, lava pours from the holes in the ceiling (pumped by hidden jets) each in a 10-foot wide line. It falls onto 1d3 random squares in each of the two sections split by the middle grille. If a creature is in the same square as one of these ceiling lava jets when it activates, it must make a successful DC 15 Dexterity saving throw or take 6d6 fire damage and be knocked prone, resulting in a fall if it was flying, levitating, or clinging to a grille (see Falling Into Lava, below). On a successful save, the creature takes half damage and is not knocked prone. These lava jets fire for 1 round, then stop.
• On round 6, lava oozes into the newly sunken squares. The level rises 5 feet every round until it reaches floor level. This deals 10d6 fire damage to any creature that comes into contact with it, or half damage with a successful DC 15 Dexterity saving throw.
• At the end of round 6, lava pours from the holes in the ceiling onto 1d3 random squares in each of the two sections split by the middle grille. If a creature is in the same square as one of these ceiling lava jets when it activates, it must make a DC 15 Dexterity saving throw or take 6d6 fire damage and be knocked prone, resulting in a fall if it was flying, levitating, or clinging to the grille.

 

These lava jets fire for 1 round, then stop.

• On round 7, any remaining squares that have not yet sunk now sink 10 feet. The entire floor is now 10 feet below normal room level and filled with molten lava.
• As the end of round 7, lava pours from the holes in the ceiling in a 10-foot wide line onto 1d3 random squares in each of the two sections split by the middle grille. If a creature is in the same square as one of these ceiling lava jets when it activates, it must make a DC 15 Dexterity saving throw or take 6d6 fire damage and be knocked prone, resulting in a fall if it is flying, levitating, or clinging to the grille.
• At the end of rounds 8-10, 1d3 lava jets fire at random for 1 round each. This should be enough to have covered all (or most) of the squares in the room at least once before the jets run out of lava.
• On rounds 11-12, the middle grille slowly retracts back into the ceiling. Any creature clinging to it at the end of round 12 falls into the lava below. Adrenaline Burnout begins (see below).
• On rounds 13-14, the grille covering the entrance slowly retracts back up into the ceiling. Any creature still clinging to it at the end of round 14 falls into the lava below.
• On rounds 15-16, the grille covering the exit slowly retracts back up into the ceiling. Any creature still clinging to it at the end of round 16 falls into the lava below.
• For the next hour, nothing else happens, but there is an intermittent stone grinding noise at 5 minute intervals accompanied by lava bubbles.
• After that hour, the lava slowly drains out of the room at the rate of 1 foot per minute. After it is gone, the floor remains 10 feet below normal room level and is still red-hot to the touch. Any creature touching the floor takes 1d6 fire damage per round it remains in contact with it.
• For the next 10 rounds after that, the floor sections randomly rise and return to their original position. The floor remains hot, and any creature touching the floor takes 1d4 fire damage per round it remains in contact with it.
• For the next 24 hours after that, the floor remains hot. Any creature touching it takes 1 point of fire damage per round it remains in contact with it. After that, the floor remains warm but non-damaging for another 24 hours. After that, it becomes cool to the touch again.

 

Lava Light: Once revealed, each lava square sheds bright fiery light in a 10-foot radius, and dim fiery light for an additional 10-feet.

Grilles: A metal grille is a variant portcullis covered by multiple metal crossbeams. Its bottom consists of a metal crossbeam rather than spikes. The spaces between the bars and crossbeams are too narrow to be squeezed through by Medium or larger creatures.

Small creatures can use all their movement for the round and lose their reaction to squeeze through. Tiny creatures can move through the openings without penalty. The crossbeams also lend stability to the grille, increasing the DC to bend its bars by +2 (see Portcullis).

Hanging Onto the Grilles: Creatures can hang onto one of the metal grilles to avoid falling into the lava, and can even attempt to climb under a grille and up its opposite side with a successful DC 13 Athletics or Acrobatics check (whichever is higher). However, anyone failing this check must succeed at a DC 15 Strength or Dexterity saving throw (player’s choice) or fall into the lava below.

On the 8th and each succeeding round, the metal grilles heat up (as a heat metal spell), dealing 2d8 fire damage per round to any creature touching them.

Falling Into Lava: Creatures that fall into the lava take 10d6 fire damage per round while submerged or partially submerged, and after they escape, they continue to take 1d6 fire damage per round from catching on fire. This damage continues until they spend a round to choose to be knocked prone and roll around to put the flames out. While doing this, they lose all their other actions and any reaction.

Adrenaline Burnout: A creature without fire immunity that remains in this trap while it is active beyond round 10 suffers 1 level of exhaustion from anxiety.

Options

To customize this trap, choose from the options below.

Smoke from the Center of the Earth: The lava emits toxic smoke. The room becomes lightly obscured on round 5. It becomes heavily obscured on round 8. Anything dropped on the ground is swiftly obscured by the smoke; it requires a DC 10 Perception check to find them. While the room is only lightly obscured by the smoke, Creatures that require air to breathe must make a DC 11 Constitution saving throw every round or be poisoned until they can breathe fresh air again. When the room becomes heavily obscured, the DC rises to 13 every round. Anything dropped on the ground requires a DC 12 Perception check to find it.

Sympathetic Magic: All Fire and Cloud magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 fire damage on a failed save regardless of whether it normally deals fire damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: Constructing this trap usually takes 6 months for new construction or double that time to retrofit existing construction. It requires an engineer, stonemason, and experienced blacksmiths.

Cost: It costs 20,000 gp per 10-foot section of room. Add +100 gp per 10-foot section if the holes in the ceiling are disguised by ornamental stonework.

---

Log Jam

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap releases dozens of Huge logs to roll down a steep incline. Its purpose is to both crush intruders and slow survivors by creating difficult terrain.

Related Traps: Rolling Sphere.

Trigger: There are two ways this trap may be triggered (GM’s choice, or why not both?):

1. Manually from above by one or more creatures above the logs who are aware of the trap and/or set it up themselves; or, 2. Automatically from below via a tripwire.

Spot: The tripwire is 3 inches off the ground. A successful DC 10 Perception check reveals the tripwire in bright light, while DC 13 spots it in dim light. DC 15 spots a tripwire in nonmagical darkness or concealed below murky water. If there is no tripwire, and the trap is only triggered manually, there may be no way to detect its presence before the trap is activated. This is especially true if the log jam is coming from a great height and/or recessed area (such as atop a rocky ledge or shelf) that creatures below could not logically see. If the creatures activating the trap above can potentially be seen, the GM may allow a DC 15 Perception check to spot some furtive movement from them 1 round before the trap triggers.

Disarm: A successful DC 15 Dexterity saving throw using thieves’ tools breaks the tripwire harmlessly. A character without thieves’ tools can attempt this check with disadvantage using any edged weapon or edged tool. On a failed check, the trap triggers.

Dimensions: A 30-foot-wide cone of two dozen or more Huge logs.

Number of Uses: One.

Reset: It is unlikely this trap will be reset in the same wilderness location due to all the evidence it leaves behind. If the trap is set indoors, such as in a dungeon or lumber mill, any evidence can be cleaned up or repaired. In that case, it will take a large team of Medium creatures (or a small team of Large-Huge creatures) a full day (at minimum) to reset the trap.

Effect: Activation of the trap requires all creatures present to roll initiative. The trap rolls initiative with a +8 bonus. On its turn, the log jam moves 60 feet in a straight line. It can move through creatures’ spaces, and creatures can move through its space, treating it as difficult terrain. Whenever the log jam enters a creature’s space or a creature enters its space while it’s sliding, that creature must succeed on a DC 15 Dexterity saving throw or take 25 (5d10) bludgeoning damage and be shoved back 10 feet, knocked prone, restrained (trapped under a log), and stunned until the end of its next turn. If the saving throw is failed by 5 or more, the creature is also shoved an additional 10 feet straight back (carried away by the logs). If the saving throw is successful, the creature takes half damage and is knocked prone, but is not restrained or stunned.

A creature that was buried alive can make a DC 15 Strength saving throw to free itself from the log it is pinned under. It can make a new saving throw each round for as many rounds as it has a Strength modifier (minimum of 1). If these saves fail, it must be rescued by another creature that uses an action to free it.

The log jam stops when it hits a wall or similar barrier. It can’t move around corners.

Difficult Terrain: Areas covered by the log jam become difficult terrain and remain so until cleared.

Construction Time: Constructing this trap usually takes 1 day for giants, or 1 week for barbarians, hobgoblins, orcs, rangers, or tribal warriors. Most other creatures require 2 weeks.

Cost: Potentially free from found material, or 50-100 gp if paying for the logs, labor, transport, and/or expertise.

---

Man-Trap

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap is a comprised of one or more large iron spikes or wooden stakes embedded into a board, or into a spherical or square-shaped panel attached to a spring-loaded mechanism that slams the spikes or stakes into a target. Its primary targets are trespassers.

Unlike a foot trap which is meant to capture intruders, a man-trap’s only purpose is to kill its target.

Related Traps: Foot Trap, Magic Landmine, Swinging Death.

Trigger: The trap is triggered by any Small or larger creature that touches the tripwire, which is a thin wire strung from one side of the area to the other. Tiny or incorporeal creatures do not activate the trap.

Spot: The tripwire is 3 inches off the ground. A successful DC 10 Perception check reveals the tripwire in bright light, while DC 13 spots it in dim light. DC 15 spots a tripwire in nonmagical darkness or concealed below murky water.

Disarm: A successful DC 15 Dexterity saving throw using thieves’ tools breaks the tripwire harmlessly. A character without thieves’ tools can attempt this check with disadvantage using any edged weapon or edged tool. On a failed check, the trap triggers.

Dimensions: Varies by size category of the intended target, but the trap always fits within a 5-10 foot square. Most man-traps are designed to strike Medium-size creatures at chest level, but this would strike a Small creature in the face, and Large creatures in the torso.

Number of Uses: One, unless reset.

Reset: A creature with 13 or higher Strength can manually reset the trap in 10 minutes.

Effect: When triggered, the trap is released at high velocity for maximum impact. It inflicts 4d6 piercing damage to the creature that triggered the trap. The target is also restrained and impaled and can only be freed by another creature spending an action to do so.

When the creature is freed from its impalement, it takes another 1d6 piercing damage as it is pulled free. A successful DC 17 Dexterity saving throw reduces the damage by half; it is still restrained and impaled, but can free itself by spending all its actions for the round and losing its reaction.

Huge creatures may trigger the trap but only take 1d6 points of piercing damage. They are not restrained or impaled by it. Gargantuan creatures may also trigger the trap, but are not affected by it.

Options

If you’d like to customize this trap, choose from the options below.

Bleeder: The wounds caused by the trap continue to bleed. On each round after the initial injury occurred, the wounded creature continues to lose 1 hit point per round until it or another creature spend an action to bind the wound(s) caused by the trap. Magic healing also ends this effect. While bleeding, the wounded creature leaves a trail of blood behind it that grants advantage to all rolls made to track it.

Diseased Man Trap: The spikes have not been cleaned of the gore from previous victims or have been smeared with feces. A creature hit by them must make a DC 11 Constitution saving throw or be infected with sewer plague.

Impalement Exhaustion: A creature impaled by this trap suffers 1 level of exhaustion when freed.

Poison Man Trap: The spikes have been recently coated with poison. This deals an extra 4d6 poison damage; a successful DC 13 Constitution saving throw reduces the damage by half. The GM is free to use a different poison.

Rusty Man Trap (Metal Spikes Only): The spikes are rusty and deal an extra 1d6 necrotic damage. A successful DC 13 Constitution saving throw reduces the damage by half.

Construction Time: Approximately 1 day. This requires a character proficient in Survival, often with a wilderness background, such as a barbarian, druid, ranger, tribal warrior, etc., or a guerrilla fighter or rogue trained in urban warfare.

Cost: Potentially free if constructed in the wilderness or rural areas with ready access to materials. In the city, assume it costs 1 gp if the man-trap is designed to target Small creatures, 5 gp for Medium, or 10 gp for Large. If there is a cost in the wilderness, assume it is half that of one built in the city.

---

Missing Staircase

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap consists of an unfinished or damaged downward-descending wooden, metal, or stone staircase. Roughly half its final steps are missing, potentially dropping creatures into the pit, room, or corridor below.

Related Traps: Acid Cauldron, Ankle Biter, Chute, False Door, False Staircase, Illusory Floor, Pit (Simple), Portcullis, Spiral Staircase, Wall of Spears, Wall of Spikes, Antlers, or Bone. These additional traps usually appear at or near where the staircase terminates, both to discourage caution and to hopefully cause the creature to fall off or down the stairs.

Trigger: The trap is triggered when any creature arrives at or near the end of the staircase (based on any additional traps present).

Spot: If the staircase is straight, a DC 12 Perception check made in bright light reveals that fact. If the check is made in dim light, the DC increases to 15. If it is made in nonmagical darkness, the DC increases to 17. If it is a spiral staircase, and the bottom is not visible, then there is no way to know that until you get at or near the end, and this adds +2 to the DC.

As a cost-cutting measure, sometimes missing staircases do not match the overall look or feel of normal staircases at the location; if this is the case, then a successful DC 13 Perception check reveals that fact.

Disarm: N/A

Dimensions: The entire length and width of the remaining staircase. The staircase is usually narrow (5- foot wide), and may be spiral in design to make it harder to spot the trap in time.

Number of Uses: Limitless, unless completed (to become normal stairs), destroyed, or sealed off.

Reset: N/A

Effect: The staircase abruptly terminates halfway down. Any creature that fails its Perception check falls however many feet it is to the bottom. The minimum fall is 10 feet for 3 (1d6) bludgeoning damage. There may be additional traps or other hazards waiting at the bottom, such as acid, spikes, sewage, creatures, etc.

Construction Time: It takes about a week per 10-foot section to excavate and fashion a stone staircase, plus an additional week if the steps are to be finished properly and made to match the aesthetics of other staircases in the facility. For wooden stairs, this time is halved. For metal stairs, the time is tripled. Stone staircases require an engineer and stonemason; wooden staircases require an engineer and carpenter; metal staircases require a metalsmith.

Cost: 50 gp per 10-foot long, 5-foot wide section of stone staircase, or double that cost to make it 10-foot wide. All costs for a wooden staircase are halved unless expensive wood is used, and all costs for metal stairs are tripled.

---

Murder Hole

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap is primarily used in castles and fortifications, but some dungeons or lairs may make use of it as well.

It is an opening in the ceiling of a passageway, often at the top of a stairwell, above a gate, or along the walls, sometimes protected by iron bars or a metal grille (See Portcullis).

The murder hole was created to allow defenders to drop objects (such as rocks, hot grease/oil, or boiling water) or to shoot arrows at attackers below while having total cover. Depending on the size of area to be defended, more than one murder hole could be used to ensure total coverage of an area, with overlapping areas of effect.

Related Traps: Acid Cauldron, Chute, Disease Dump, Drawbridge, Net Trap, Portcullis.

Trigger: Unlike other traps, this one must be activated manually by the defenders upon becoming aware of intruders below. If the GM wishes, the murder hole could be automatically triggered and reset by magic.

Spot: A successful DC 13 Perception check in bright light reveals the murder hole, or DC 15 in dim light, or DC 17 in nonmagical darkness.

Disarm: The trap cannot be disarmed unless its operators are somehow prevented from using it.

Dimensions: Each murder hole covers an area 10 feet in diameter and spans the full height of the area it protects. It includes a room above large enough to hold the cauldron, ammunition, and other supplies, while leaving room for a team of at least 4 defenders.

Number of Uses: One for heated contents like grease/oil or water, until refilled and manually reset. Otherwise, it is limited by the defender’s ammunition (arrows, bolts, rocks, sewage, etc.).

Reset: Refilling and reheating hot oil or boiling water in a large cauldron requires 30 minutes for a team of two or more defenders, or up to twice that long for a single defender. If using grease or oil with flammable material, additional precautions must be taken during a reset, such as having water buckets nearby filled with sand to douse any fires caused by escaping oil.

Effect: When triggered by the defenders, the trap releases its contents through the murder hole in the ceiling above. Assuming it is a heavy iron cauldron suspended on chains with a mechanism for safe and easy pouring, then the effect on any creatures below depends on the contents.

Choose or roll 1d4 on the list below:

1. Boiling Water: This deals 1d6+1 fire damage and the target is knocked prone. The area is lightly obscured for 2 rounds.
2. Burning Grease: This deals 2d6+2 fire damage per round and the target is on fire and continues to 1d6+1 fire damage each round until it or another creature spend an action putting out the flames. The area is heavily obscured for 1 round and lightly obscured for 1 round thereafter.
3. Hot Oil: This deals 4d8+4 fire damage and the target is knocked prone. The area is heavily obscured for 3 rounds and lightly obscured for 3 rounds thereafter.
4. Raw Sewage (Not Heated): The target is knocked prone and must make a successful DC 11 Constitution saving throw or be infected by sewer plague and is poisoned until it washes the reeking filth off.

All of these attack options have a 10-foot strike zone and 10-foot splash zone:

• Any creature directly beneath the murder hole’s 10-foot “strike zone” takes full damage.
• Any creature up to 10 feet away is in the “splash zone” and takes half damage.

Regardless of distance, all creatures affected can attempt a DC 13 Dexterity saving throw. On a success, they take half damage if in the strike zone or no damage if in the splash zone. In either case, they are not knocked prone/on fire/diseased.

Options

To customize this trap, choose from the options below.

Boiling Acid: The murder hole uses boiling acid to deal an extra 2d6 acid damage per round to any creature exposed to it; a successful DC 13 Dexterity saving throw reduces the acid damage by half. In addition, the area is lightly obscured due to steam.

Paralyzing Slime: The murder hole uses paralyzing slime instead of water. A creature attempting to enter, move through, or escape the coated area at the start of its turn must make a DC 14 Constitution saving throw or be paralyzed for 1 minute. If it fails, it is also knocked prone by a sudden wave of nausea causing it to slip in the slime. Creatures in heavy armor save against this with advantage. A paralyzed creature can make a new save each round to negate the condition.

Paralyzed prone creatures may drown in the slime, depending on if they fell face-down and how much slime is poured on them (this would have to be a lot).

Construction Time: Constructing this trap usually takes about 4 weeks for new construction or double that to retrofit existing construction. An engineer and stonemason are required, and special attention must be paid to the plumbing, ventilation, and heating system.

Cost: Each murder hole costs 250 gp for new construction or double that for existing construction, plus 100 gp for the cost of the heavy iron cauldron, its chains, and suspension system.

---

Net Trap

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap uses a tripwire to release a net suspended from the ceiling or between two columns or trees.

Related Traps: Disease Dump, Foot Trap.

Trigger: The trap is triggered by any Small or larger creature that touches the tripwire, which is a thin wire strung from one side of the area to the other. Tiny or incorporeal creatures do not activate the trap.

Spot: The net is hidden by cobwebs or foliage. The tripwire is 3 inches off the ground. A successful DC 10 Perception check reveals the tripwire in bright light, while DC 13 spots it in dim light. DC 15 spots a tripwire in nonmagical darkness or concealed below murky water.

Disarm: A successful DC 15 Dexterity saving throw using thieves’ tools breaks the tripwire harmlessly. A character without thieves’ tools can attempt this check with disadvantage using any edged weapon or edged tool. On a failed check, the trap triggers.

Dimensions: The tripwire is 3 inches off the ground and stretches between two columns or trees.

Number of Uses: One, until manually reset.

Reset: A single creature proficient in Survival can set or reset the trap in 10 minutes.

Effect: When the trap is triggered, the net is released, covering a 10-foot-square area. Those in the area are trapped under the net and restrained, and those that fail a DC 10 Strength saving throw are also knocked prone. A creature can use its action to make a DC 10 Strength check, freeing itself or another creature within its reach on a success.

The net has AC 10 and 20 hit points.

Dealing 5 slashing damage to the net (AC 10) destroys a 5 foot square section of it, freeing any creature trapped in that section.

Options

To customize this trap, choose from the options below.

Barbed Chain Net: When the trap is triggered, this sturdy (10 lb.) chain link net is released, covering a 10-foot-square area. Those in the area are trapped under the net and restrained, and those that fail a DC 12 Strength saving throw are also knocked prone.

Regardless, any creature in the net takes 1 piercing damage per round from the cruel barbs forged into it; these also make the net harder to remove or escape from. A creature can use its action to make a DC 14 Strength check, freeing itself or another creature within its reach on a success.

The barbed chain net has AC 14 (natural armor) and 40 hit points. It cannot be cut by nonmagical weapons. Dealing 10 slashing damage to the net with a magical weapon destroys a 5 foot square section of it, freeing any creature trapped in that section.

Suspension Net: Rather than falling from above, this heavier and sturdier version is hidden on the ground (usually concealed under foliage). When the trap is triggered, the net is lifted up to hang 10 feet off the ground—along with any creatures that fail a DC 13 Dexterity saving throw. Creatures caught in a suspension net are restrained until freed, and the only way to free them is by cutting the net (and then taking 1d6 bludgeoning damage from the fall). This is a heavy cargo net with AC 12 and 30 hit points. Dealing 10 slashing damage to it destroys a 5 foot section.

Construction Time: The basic rope net or suspension net can be hand-woven in a week. A barbed chain net requires 2 weeks and a blacksmith.

Cost: 2 gp for a basic net, 3 gp for a suspension net with rope, or 50 gp for a barbed chain net.

---

Pendulum Gauntlet

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

The trap consists of multiple pendulum blades swinging over a tight bridge, corridor, or room. The blades swing at tremendous speed, slicing any creature in their path. To avoid the blades, a creature needs to time its movements carefully.

Related Traps: Guillotine Door, Swinging Death.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to a pressure plate, which is a concealed section of floor that immediately descends several inches when stepped on. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful Perception check reveals the trap’s presence, either through a discolored pressure plate (DC 15) or via the recessed apertures in the ceiling and walls that house and permit the movement of the pendulum blades (DC 13). Add +2 to the check DC in dim light or +4 in nonmagical darkness.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered.

The trap can also be disarmed via a control room accessed via a secret door on its opposite side. The secret door can be found with a successful DC 17 Investigation check. Once the room is accessed, the trap can be disarmed in one of two ways:

1. By jamming the gears with magic or with sturdy Medium or larger objects. This requires a successful DC 17 Strength check per pendulum blade. If the check fails, the object breaks and the pendulum continues to swing as before. This could be a case where it is possible to jam some, but not all, of the pendulum blades in this manner.
2. The smarter solution to disarm the trap is with a successful DC 17 Dexterity saving throw using thieves’ tools. This involves disabling the mechanism that sets off and powers the trap, slowing the blades and shutting it down completely in 3 rounds. While slowing, the blades deal half damage. After this, the trap remains disarmed until manually reset.

Dimensions: The trap spans the entire length and width of a specific narrow bridge, corridor, or room, plus the adjacent or nearby secret control room. The trap works best in enclosed spaces such as corridors no more than 5 to 10 feet wide and up to 40 feet long where there are no obstacles to impede its function.

Number of Uses: Limitless, until jammed/disarmed.

Reset: The trap stops and resets itself after 10 minutes. When this occurs, the blades gradually slow (dealing half damage) over 3 rounds, then retreat back inside the walls where they return to their previously locked positions.

Effect: Activation of the trap requires all creatures present to roll initiative. The trap rolls initiative with a +8 bonus. When triggered by attempting to “run the gauntlet” and pass through the trap’s area of effect, four large pendulum blades swing outwards from hidden compartments:

• Pendulum #1 swings from the left wall to the right.
• Pendulum #2 swings from the right wall to the left.
• Pendulum #3 swings from the left wall to the right.
• Pendulum #4 swings from the right wall to the left.

Each pendulum’s arc starts at waist height and ends its trajectory just above head height for a Medium-size creature.

These blades must be dodged by timing their swings to move after a blade has completed its arc into the opposite wall. This requires a successful Dexterity saving throw to move through in time. The DC is set by how many blades a creature attempts to bypass

• Bypass 1 Blade: DC 15
• Bypass 2 Blades: DC 17
• Bypass 3 Blades: DC 19
• Bypass 4 Blades: DC 21

If a creature elects to clear the entire trap in 1 round, then the DC is 21, and only rolled once. If it elects to clear only one blade at a time, the DC is 15, rolled 4 times over 4 rounds. If it elects to clear the first two blades, then pause, the DC is 17, rolled once, and it can decide whether to clear each remaining blade one round at a time (DC 15) or both remaining blades (DC 17) at once on its next turn.

Unless a creature chooses to bypass all four blades, it must end its movement in the square immediately before the next blade and it loses its reaction. These options assume a creature has sufficient movement to reach the opposite side; if it doesn’t, then reduce the number of blades it can bypass on its turn accordingly.

Creatures that fail their saving throw take 4d8+4 slashing damage from the first (or next) blade in the trap and are shoved into the adjoining wall the blade is traveling into (taking an extra 1d6 bludgeoning damage in the process), or, if the trap is over a bridge, then it falls into the pit or chasm below. Pits for this trap are a minimum of 30-feet deep (dealing 3d6 bludgeoning damage) and may contain additional hazards such as spikes, creatures, acid, lava, diseased sewage, or other dangerous substances of the GM’s choice.

Once a creature bypasses all 4 blades, it suffers 1 level of exhaustion from all the anxiety the trap caused. Creatures immune to slashing damage or that can bypass the trap without being threatened by it do not suffer this exhaustion.

Options

To customize this trap, choose from the options below.

Bleeder: The wounds caused by this trap continue to bleed. On each round after the initial injury occurred, the wounded creature continues to lose 1 hit point per round until it or another creature spend an action to bind the wound(s) caused by the trap. Magic healing also ends this effect. While bleeding, the wounded creature leaves a trail of blood behind it that grants advantage to all rolls made to track it.

Diseased Blade: The blade has not been cleaned of the gore from its previous victims. A creature hit by it must make a DC 11 Constitution saving throw or be infected with sewer plague.

Living Blade: The trap is a construct that resets itself automatically. Because it can time its attack perfectly, the saving throw DC is increased to 17. In addition, the trap can relentlessly blare and repeat a preprogrammed magic mouth alarm, such as maniacal laughter, but cannot otherwise communicate. A living pendulum blade has AC 18 (natural armor) and 50 hit points. It cannot move outside its appointed trajectory.

The trap radiates illusion magic when this option is added.

Poison Blade: The blade has been recently poisoned.

It deals an extra 2d6 poison damage; a successful DC 13 Constitution saving throw reduces the damage by half. The GM is free to use a different poison if desired.

Rusty Blade: The blade is rusty and deals an extra 1d6 necrotic damage. A successful DC 13 Constitution saving throw reduces the damage by half.

Construction Time: Constructing this trap usually takes about 8 weeks for new construction or double that to retrofit existing construction. Triple that time if a bridge and pit/chasm is involved. An engineer, stonemason, blacksmith, and carpenter are all required.

Cost: 2,500 gp for new construction or double that for existing construction. Triple the cost if a bridge and pit/chasm is involved. If more than 4 pendulums are needed to extend the trap’s dimensions, add an additional 500 gp per pendulum.

---

Pit (Flooded)

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

A flooded pit trap is a hole dug in the ground and filled with liquid and/or decomposing matter. Outdoors, the hole is either left open or covered by a large cloth anchored on the pit’s edge and camouflaged with dirt and debris. Indoors, it can be left open or covered, and its cover can also include the Hidden, Locking, and/or Spiked options (see below). See also Ditch, Moat, or Pit (Hidden) for bigger or better concealed varieties.

Related Traps: Acid Cauldron, Entombed In Ice, Flood Zone, Pit (Hidden), Pit (Simple), Quicksand, Quickslime, Sinkhole.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to the trapped section of ground or floor. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 10 Perception check spots an unconcealed pit in bright light, DC 12 in dim light, or DC 13 in nonmagical darkness (due to reflections on the water’s surface). If the pit is concealed, add +2 to the DC. If the pit is unconcealed but flooded to at or near the top, then it can be mistaken for a not too deep puddle or possibly overlooked if the rest of the area around it is underwater, In either case, this adds an extra +2 to the DC on top of any from the lighting. If the pit’s cover uses or combines the Hidden or Locking options, refer to those options for the increased DC.

Disarm: The pit must be filled in with dirt or debris to be truly disarmed; removing the cover (if any) makes it easier to spot and avoid.

Dimensions: Most flooded pit traps are 10-feet wide and 10-feet deep. Larger versions (in width and/or depth) exist. The height of the water or other liquid in the pit varies, but the default is for it to be half-full unless the trap-maker intended for it to be higher or lower.

Number of Uses: Limitless, until filled in.

Reset: A flooded pit trap can be reused as often as it can be cleaned out and re-camouflaged; this is more difficult than non-flooded pits and takes roughly 6d6 minutes (1 hour if bodies must be removed).

Effect: Once triggered, the creature who triggered the trap must succeed on a DC 12 Dexterity saving throw. If it fails, it falls into the pit and takes 1d3 bludgeoning damage for every 10 feet it falls. This damage is half that of an un-flooded pit; the damage comes from bouncing off the walls rather than hitting bottom. If the pit is concealed, anyone stepping on the cloth falls through and pulls the cloth into the pit.

Options

To customize this trap, choose from the options below.

Abandoned Well: You can substitute an old, abandoned well for a flooded pit. In this case, the top has been covered by leaves, dirt, and rotten boards. It is ground-level, without the traditional built-up outer stone rim or overhead roof. The rope and pulley system and bucket with ladle are also gone, though all or any of these may exist (mostly as rubble) nearby.

Stepping on the boards over the mouth of the well causes them to break, with the result of falling into the pit as above. The only other difference is that the first creature to fall into the well also suffers the boards falling on top of them for an extra 1d3 bludgeoning damage beyond that from bouncing off the walls.

Acid Cauldron: This version of the trap is filled with acid instead. Both hydrochloric and nitric acid melt stone, so only lye or sulfuric acid may be used. See Acid Cauldron.

Creature: The pit contains one or more creatures (including swarms) of the GM’s choice, most likely amphibious or aquatic beasts, insects, or rats. These creatures may have been placed there by the trapmaker, or they may have fallen in and become trapped themselves. Unless undead, immortal, or extremely long-lived, most creatures would have had to have become trapped within the past day or else they will have drowned as soon as they fell asleep unless they had a floating board or s other object to keep their head above water.

Dirty Water: If the GM desires, the water in flooded pits can be contaminated, such as with raw sewage, parasites, and/or decomposing bodies. A creature who falls in must make a DC 11 Constitution or Dexterity saving throw (whichever score is higher) it is in the pit or be poisoned for a number of hours equal to 10 – its CON modifier (if positive).

Diseased: The liquid in the well has been contaminated with bacteria, raw sewage, or liquefying diseased fluids/remains. Any creature that enters the pit (whether by falling in or not) must make a DC 11 Constitution saving throw or contract sewer plague. Optionally, you can choose a different disease or spores from this or another book, such as those listed in our Game Master’s Guide to Traits & Actions for Monsters & NPCs. These include brain swell, cackling cough, pus popper, sinister sneeze, vomit plague, and watery bowels. Other possibilities include magical diseases like lycanthropy or vampirism. If flooded by raw sewage, this pit might connect to a sewer system. If it does, it will include a flooded Tunnel (see below), perhaps protected by a metal grille (see Portcullis).

Hidden: See Pit (Hidden).

Locking (Indoor Only): This flooded pit trap is identical to a Hidden Pit trap, with one key exception: the trap door that covers the pit is spring-loaded. After a creature falls into the pit, the cover snaps shut to trap its victim inside. A successful DC 20 Strength check is necessary to pry the cover open. The cover can also be smashed open. A character in the pit can also attempt to disable the spring mechanism from the inside with a DC 15 Dexterity saving throw using thieves’ tools, provided that the mechanism can be reached and the character can see. In some cases, a mechanism (usually hidden behind a secret door nearby) opens the pit.

Low Water Level: The water line in this pit was either never filled properly or has partially evaporated or drained away. Creatures trapped inside cannot drown if they fall asleep because the water does not rise past their heads when sitting. However, less water in the pit increases falling damage back to normal (1d6 per 10 feet fallen).

Prison Bars (Indoor Only): 1 round after it is triggered, metal prison bars extend across the top of the pit where the cover was and lock into place. The pit must be manually reset to withdraw the bars and until it is, it is effectively disarmed, becoming a prison cell. The bars may be bent by a creature outside the pit with 17 or higher Strength and sufficient leverage by making three successful DC 17 Athletics checks. Creatures that are Large or bigger reduce the Athletics DC by -2 per size category above Medium. After the third successful check—and assuming it can fit—a creature in or out of the pit can squeeze between the bars by using all of its movement for the round and losing its reaction. It ends up knocked prone in an unoccupied square adjacent to the trap.

Small Creature Safe (Indoor Only): This pit is only triggered by Medium-size creatures or larger. It is designed by Small humanoids (dwarves, goblins, kobolds, etc.) so they can lure larger enemies across it without triggering the trap themselves. This option must be combined with either the Hidden or Locking options.

Spiked: This pit trap is a Simple, Hidden, or Locking pit trap with sharpened wooden or iron spikes at the bottom. A creature falling into the pit takes 11 (2d10) piercing damage from the spikes, in addition to any falling damage. Even nastier versions have poison smeared on the spikes. In that case, anyone taking piercing damage from the spikes must also make a DC 13 Constitution saving throw, taking an extra 22 (4d10) poison damage on a failed save, or half as much damage on a successful one. See also Necrotic Bone Spikes or Wall of Spikes, Bone, or Antlers.

Construction Time: 8 hours per 10 feet of depth and 5 feet of width, assuming a single Medium creature with a Strength of 10 or higher is doing the digging, or half that time if two or more Medium creatures combine their efforts. Double that time for Small creatures, and quadruple it for Tiny ones.

Large creatures can construct a 10 foot deep, 10 feet wide pit in 2 hours (or half that time if two of them work together). Huge creatures can construct a 20-foot deep, 20 feet wide pit in 1 hour (or half that time if two of them work together). Gargantuan creatures generally do not construct pits, but some unintentionally create them by burrowing (see also Sinkhole).

Note that frozen ground or hard-packed dirt are unacceptable for digging unless magic is used to remove or soften the ground.

This type of pit needs to be flooded; allow additional days or weeks (depending on weather) for it to be left uncovered to be filled by rainwater in any season except summer, or however much time is needed to cart in the amount of water or other liquid desired.

Cost: 10 gp for a dirt pit or 35 gold for a stone pit (including the labor, picks, shovels, and expertise).

Water to flood the pit is included in the cost but other liquids are extra (see Acid Cauldron for one such example). These costs also include carting the dirt or debris away. Costs double for each additional 10 feet of depth to be added to the pit. Add 10 gp for the Spiked option, and 100 gp for the Locking or Prison Bars option. Creature option costs vary by creature type and its difficulty to obtain and transport.

A pit with moving parts (like Hidden, Locking, or Prison Bars demand) requires an engineer and 1 extra week to complete regardless of depth.

---

Pit (Hidden)

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This indoor-only stone pit has a clever cover constructed from material identical to the floor around it. This is the most common type of pit found in worked stone dungeons. About half of those encountered will also feature the Locking option (see below).

Related Traps: Entombed In Ice, Pit (Flooded), Pit (Simple), Sinkhole.

Trigger: The trap is triggered by applying 20 pounds or more of pressure to the trapped section of ground or floor. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 15 Perception check in bright light discerns an absence of foot traffic over the section of floor that forms the pit’s cover. The DC increases to 17 in dim light or 19 in nonmagical darkness. A successful DC 15 Investigation check is necessary to confirm that the trapped section of floor is actually the cover of a pit.

Disarm: Once the pit trap is detected, an iron spike or similar object can be wedged between the pit’s cover and the surrounding floor in such a way as to prevent the cover from opening, thereby making it safe to cross. The cover can also be magically held shut using the arcane lock spell or similar magic.

Dimensions: Most hidden pit traps are 10-feet wide and 10-feet deep. Larger versions (in width and/or depth) exist.

Number of Uses: Limitless, until filled in.

Reset: An outdoor pit trap can be reused as often as it can be cleaned out and re-camouflaged; this takes roughly 2d6 minutes (30 minutes if bodies must be removed). An indoor pit trap can be manually reset and may reused as often as needed.

Effect: When a creature steps on the cover, it swings open like a trapdoor, causing the intruder to spill into the pit below. The pit is usually 10 to 30 feet deep.

The creature who triggered the trap must succeed on a DC 12 Dexterity saving throw. If it fails, it falls into the pit and takes 1d6 bludgeoning damage for every 10 feet it falls.

Options

To customize this trap, choose from the options below.

Creature: The pit contains one or more creatures (including swarms) of the GM’s choice. These creatures may have been placed there by the trapmaker or may have fallen in and become trapped themselves. Unless undead, immortal, or extremely long-lived, most creatures would have had to have become trapped within the past week and are likely starving. For this reason, any creature placed on purpose in the pit would likely be a construct, ooze, plant, or undead.

Flooded: See Pit (Flooded).

Locking: This indoor-only pit trap is identical to a Hidden Pit trap, with one key exception: the trap door that covers the pit is spring-loaded. After a creature falls into the pit, the cover snaps shut to trap its victim inside. A successful DC 20 Strength check is necessary to pry the cover open. The cover can also be smashed open. A character in the pit can also attempt to disable the spring mechanism from the inside with a DC 15 Dexterity saving throw using thieves’ tools, provided that the mechanism can be reached and the character can see. In some cases, a mechanism (usually hidden behind a secret door nearby) opens the pit.

Prison Bars (Indoor Only): 1 round after it is triggered, metal prison bars extend across the top of the pit where the cover was and lock into place. The pit must be manually reset to withdraw the bars and until it is, it is effectively disarmed, becoming a prison cell.

The bars may be bent by a creature outside the pit with 17 or higher Strength and sufficient leverage by making three successful DC 17 Athletics checks.

Creatures that are Large or bigger reduce the Athletics DC by -2 per size category above Medium. After the third successful check—and assuming it can fit—a creature in or out of the pit can squeeze between the bars by using all of its movement for the round and losing its reaction. It ends up knocked prone in an unoccupied square adjacent to the trap.

Small Creature Safe (Indoor Only): This pit is only triggered by Medium-size creatures or larger. It is designed by Small humanoids (dwarves, goblins, kobolds, etc.) so they can lure larger enemies across it without triggering the trap themselves. This option must be combined with either the Hidden or Locking options.

Spiked: This pit trap is a Simple, Hidden, or Locking pit trap with sharpened wooden or iron spikes at the bottom. A creature falling into the pit takes 11 (2d10) piercing damage from the spikes, in addition to any falling damage. Even nastier versions have poison smeared on the spikes. In that case, anyone taking piercing damage from the spikes must also make a DC 13 Constitution saving throw, taking an extra 22 (4d10) poison damage on a failed save, or half as much damage on a successful one. See also Necrotic Bone Spikes or Wall of Spikes, Bone, or Antlers.

Construction Time: 8 hours per 10 feet of depth and 5 feet of width, assuming a single Medium creature with a Strength of 10 or higher is doing the digging, or half that time if two or more Medium creatures combine their efforts. Double that time for Small creatures, and quadruple it for Tiny ones. Large creatures can construct a 10 foot deep, 10 feet wide pit in 2 hours (or half that time if two of them work together). Huge creatures can construct a 20-foot deep, 20 feet wide pit in 1 hour (or half that time if two of them work together). Gargantuan creatures generally do not construct pits, but some unintentionally create them by burrowing (see also Sinkhole).

A pit with moving parts (like Hidden, Locking, or Prison Bars demand) requires an engineer and 1 extra week to complete regardless of depth.

Note that frozen ground or hard-packed dirt are unacceptable for digging unless magic is used to remove or soften the ground.

Cost: 50 gp for a Hidden Pit (including the labor, picks, shovels, and expertise). These costs also include carting the rubble away. Costs double for each additional 10 feet of depth to be added. Add 10 gp for the Spiked option, and 100 gp for the Locking or Prison Bars option. Creature option costs vary by creature type and its difficulty to obtain and transport.

---

Pit

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap Simple

A simple pit trap is a hole in the ground. It is covered by a large cloth anchored on the pit’s edge and camouflaged with dirt and debris.

Related Traps: Entombed In Ice, Pit (Flooded), Pit (Hidden), Sinkhole.

Trigger: If concealed, the trap is triggered by applying 20 pounds or more of pressure to the trapped area. Tiny or incorporeal creatures do not activate the trap.

Spot: A successful DC 10 Perception check in bright light discerns an absence of foot traffic over the section of floor that forms the pit’s cover. The DC increases to 12 in dim light or 14 in nonmagical darkness.

Disarm: The pit must be filled in to be truly disarmed; removing the cover (if any) makes it easier to spot and avoid.

Dimensions: Most pit traps are 5-feet wide and 10- feet deep. Larger versions (in width and/or depth) exist. The next most common design is 10 feet wide by 10 feet deep, followed by 10 feet wide by 20 feet deep.

Number of Uses: Limitless, until filled in.

Reset: An outdoor pit trap can be reused as often as it can be cleaned out and re-camouflaged; this takes roughly 2d6 minutes (30 minutes if bodies must be removed). An indoor pit trap can be manually reset and may reused as often as needed.

Effect: Once triggered, the creature who triggered the trap must succeed on a DC 12 Dexterity saving throw. If it fails, it falls into the pit and takes 1d6 bludgeoning damage for every 10 feet it falls. If the pit is concealed, anyone stepping on the cloth falls through and pulls the cloth down into the pit.

Options

To customize this trap, choose from the options below.

Creature: The pit contains one or more creatures (including swarms) of the GM’s choice. These creatures may have been placed there by the trapmaker or may have fallen in and become trapped themselves. Unless undead, immortal, or extremely long-lived, most creatures would have had to have become trapped within the past week and are likely starving. For this reason, any creature placed on purpose in the pit would likely be a construct, ooze, plant, or undead.

Flooded: See Pit (Flooded).

Open Grave: The pit is actually an unmarked open grave. It may or may not contain a corpse and/or coffin. If it does, the corpse may be diseased or undead, but might also contain some jewelry, treasure, or clue to a greater mystery. Grave robbers or ghouls may be lurking nearby, scared off by the party’s approach.

Spiked: This pit trap is a Simple, Hidden, or Locking pit trap with sharpened wooden or iron spikes at the bottom. A creature falling into the pit takes 11 (2d10) piercing damage from the spikes, in addition to any falling damage. Even nastier versions have poison smeared on the spikes. In that case, anyone taking piercing damage from the spikes must also make a DC 13 Constitution saving throw, taking an extra 22 (4d10) poison damage on a failed save, or half as much damage on a successful one. See also Necrotic Bone Spikes or Wall of Spikes, Bone, or Antlers.

Structural Damage: This pit is the result of damage to the area’s roof or floor, perhaps due to an earthquake or thunder magic. As such, it will be irregularly formed and filled with debris, corpses, etc. It may or may not lead into another area.

Tunnel: The pit leads into a tunnel. This may or may not be have been dug by burrowing monsters; its existence may be completely unknown to (or unintended by) the trap-maker or part of a new project.

Construction Time: 8 hours per 10 feet of depth and 5 feet of width, assuming a single Medium creature with a Strength of 10 or higher is doing the digging, or half that time if two or more Medium creatures combine their efforts. Double that time for Small creatures, and quadruple it for Tiny ones. Large creatures can construct a 10 foot deep, 10 feet wide pit in 2 hours (or half that time if two of them work together). Huge creatures can construct a 20-foot deep, 20 feet wide pit in 1 hour (or half that time if two of them work together). Gargantuan creatures generally do not construct pits, but some unintentionally create them by burrowing (see also Sinkhole). Note that frozen ground or hard-packed dirt are unacceptable for digging unless magic is used to remove or soften the ground.

Cost: 2 gp for a dirt pit or 25 gold for a stone pit (including the labor, picks, shovels, and expertise).

These costs also include carting the dirt or debris away.

Costs double for each additional 10 feet of depth to be added to the pit. Add 10 gp for the Spiked option.

Creature option costs vary by creature type and its difficulty to obtain and transport.

---

Poison Needle

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

A poisoned needle is hidden within a lock, such as might be found on a treasure chest, coffer, or jewelry box, the door to a secret room or tomb, or another object a creature might open.

Related Traps: Statue of Poison Darts, Wall of Poison Darts.

Trigger: Opening the object without the proper key causes the needle to spring out.

Spot: A successful DC 20 Investigation check allows a character to deduce the trap’s presence from alterations made to the lock to accommodate the needle.

Disarm: A successful DC 15 Dexterity saving throw using thieves’ tools disarms the trap, removing the needle from the lock. Unsuccessfully attempting to pick the lock triggers the trap.

Dimensions: The size of the lock (usually Tiny).

Number of Uses: One, until reset.

Reset: A single creature can safely re-coat the needle with poison and reset this trap in 5 minutes.

Effect: When the trap is triggered, the needle extends 3 inches straight out from the lock. A creature within range takes 1 piercing damage and 11 (2d10) poison damage, and must succeed on a DC 15 Constitution saving throw or be poisoned for 1 hour. This is the most common type of poison used in needle traps; the GM is free to use a different type of poison, such as paralysis, sleep, etc.

Options

To customize this trap, choose from the options below.

Diseased Needle: Some versions of this trap (perhaps those where the owner ran out of poison) may be coated with diseased fluids instead. This could be the normal kind that forces a DC 11 Constitution saving throw to avoid being infected with sewer plague. Optionally, you can choose a different disease from the DMG or another book, such as those listed in our Game Master’s Guide to Traits & Actions for Monsters & NPCs. These include brain swell, cackling cough, pus popper, sinister sneeze, vomit plague, and watery bowels.

Other possibilities include magical diseases like lycanthropy or vampirism.

Sleep Needle: This version of the trap puts a creature pricked by the needle to sleep for a number of hours equal to 6 – its Constitution modifier. A successful DC 17 Constitution saving throw merely makes the creature drowsy for 1 hour instead and imposes a -1 penalty to all attack rolls, saving throws, and skill checks. While asleep from this poison, a creature may be mistaken for dead as it drastically lowers their pulse and heart rate. A DC 20 Medicine check reveals the creature is comatose and not dead. Nothing short of magic that removes the poison can wake the sleeping creature. This type of poison is used less for trapping random treasure chests in dungeons and more for trapping “gift boxes” to make someone appear dead to facilitate a kidnapping, inheritance, or other crime.

Swarm Needle: This version of the trap is magical and radiates conjuration magic. It summons a swarm of insects that emerge from the lock’s keyhole and attack all creatures present, with a preference for the one that triggered the trap. If the GM wishes, the swarm’s bite can be poisonous as well, the type of which will match the saving throw DC and damage of the trap’s poison needle.

Construction Time: Typically 1 week to craft the lock and 1 hour to install and test. Acquiring the poison can be variable depending on legality and connections.

Cost: 100 gp plus the cost of the poison. A trap with a higher DC to disarm doubles the cost for every +2 it adds. For example, a DC 17 to disarm trap costs 200 gp. See Trap Options for ideas.

---

Portcullis

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap consists of a pressure plate embedded in the floor connected to a large metal portcullis. A portcullis is usually made from thick iron bars (like a prison cell) with reinforced cross bar support and sharp spikes at the bottom. It is usually placed near or in front of a strategic door, gate, or passageway to trap intruders and restrict access to valuable items or personnel.

Related Traps: Drawbridge, Lava Doom, Moat, Murder Hole.

Trigger: The trap can be triggered by applying 20 pounds or more of pressure to a pressure plate, or it can be manually operated by pulling a lever from an observation room directly above, such as in a castle or city gate. Tiny or incorporeal creatures do not activate the pressure plate version.

Spot: To spot this trap requires a successful DC 10 Perception check if unconcealed or DC 15 if concealed. A successful check reveals there is a narrow aperture in the ceiling running above the room or passage that likely leads to some sort of gate, grille, or portcullis mechanism above.

The usual way to conceal this trap is to place it above a door or archway with a decorative and/or reinforced mantle over it, typically with gargoyles, symbols, or other ornamentation built in. This overhang draws attention to it and makes it harder to spot the recessed aperture.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered. If it is manually operated from an observation room above, the guards and operator must be defeated and the lever pulled that operates the portcullis. This lever can be permanently broken by a creature with an 18 Strength score or higher making a successful DC 17 Athletics check, or temporarily jammed by an item or spell that prevents the lever from moving.

Dimensions: A standard interior castle, dungeon, or sewer portcullis is approximately 10-feet tall, 10-feet wide. It is designed to perfectly fit the stone room, arch, or passageway beneath it, so the size may vary.

A standard exterior castle or city portcullis (such as is typically encountered at a gate or drawbridge) is 20- feet tall and 20-feet wide to accommodate mounts, wagons, and Huge creatures.

Number of Uses: One, until reset.

Reset: Not unless someone manually sets it back into position against its counterweight system. There will always be a concealed access point to get up into the trap’s mechanics, but this is never located on the same side as the trap is meant to keep intruders from moving past. To find the access point requires a successful DC 15 Investigation check.

Effect: When triggered, a hidden rope and pulley system drops the portcullis into place. This is accompanied by a loud clang that can be heard for 300 feet in every direction if it closes on metal or stone, or 150 feet if it closes on dirt. As such, the portcullis also functions as a brief 1 round alarm system. Any creature within 5 feet of the portcullis when it drops must make a DC 15 Dexterity saving throw or be unable to move out of the way in time to avoid being trapped inside when the portcullis slams down behind them. If the save fails by 5 or more, then the creature is struck by the falling portcullis and impaled beneath it. This deals 2d6 bludgeoning and 1d6 piercing damage and the creature is restrained until the portcullis is raised enough for them to pull themselves free or be pulled free by another creature. If the save fails by 10 or more, the trap deals a critical hit and the creature is stunned until the start of its next turn and restrained as detailed above.

Bending the Bars: To bend the portcullis bars requires a series of Athletics checks made by a creature with 17 Strength or higher. The first check is DC 17 and bends the bars enough for one Small creature per round to squeeze through using all their movement for the round and causing them to lose their reaction. The second check is DC 15 and does the same for a Medium creature. The third check is DC 13 and does the same for a Large creature. If the bars are rusty, reduce all DCs by -2. If the creature bending them is Huge-Gargantuan, it gains advantage on its checks.

DESTRUCTION

A standard interior portcullis has 120 hit points and a standard exterior portcullis has 200 hit points. Both are immune to all damage except acid, bludgeoning, and force.

Lifting the Portcullis: To lift a portcullis requires a series of Athletics checks. The first check is made at DC 15 and lifts the bars enough for one Small-Medium creature per round to crawl through. This uses all the lifting and crawling creatures’ movement for the round and causes them to lose their reactions.

The second check is DC 17 and does the same for two medium creatures to crawl through, or up to four Small creatures (assuming there is enough floorspace).

The third check is DC 13 and does the same for a single Large creature to crawl through. If the bars are rusty, reduce all DCs by -2. If the creature bending them is Huge-Gargantuan, it gains advantage on its checks.

Squeezing Through Unbent Bars: Any creature attempting to squeeze past the bars of an intact portcullis must be Small (and thin, which rules out stockier species like dwarves). This uses up all its movement for the round and it loses its reaction. If it succeeds on a DC 15 Dexterity saving throw, it is able to squeeze through the bars and emerges on the other side. If the save fails by 5 or more, the creature is stuck between the bars, suffers 1 level of exhaustion, and restrained. It is allowed a new saving throw with disadvantage every round until it succeeds.

A creature with the Squeeze trait (like oozes) use up half its movement for the round as it squeezes through, but does not lose its reaction. In addition, it does not need to make a saving throw.

Options

To customize this trap, choose from the options below.

Blast Door (Variant): A blast door is an iron door without a knob, knocker, lock, or ring that can only be opened by resetting the trap or destroying it. It is easier to spot (reduce Perception DC by -2) because there is a metal aperture in the floor for the bottom to snugly slot into. This makes it impossible to lift since there is no way to get your fingers under it, and there are no bars to bend or spaces to squeeze through.

Blast doors protect the location from all fire and other area effect damage. Left sealed, blast doors also seal off the area from any new oxygen intake.

A blast door has 300 hit points. It is immune to all damage except acid, bludgeoning, and force.

Double Portcullises: A pair of portcullises drop down at the same time. Usually, this is to seal off an entrance and an exit, but in some cases, the portcullises are doubled in the same direction but spaced apart by 10- 20 feet. This is designed to split up larger parties by trapping one or more members inside a 10-20 foot section of corridor, and/or to buy defenders more time by doubling the number of portcullises intruders must get past.

Grille (Variant): A metal grille is a variant portcullis covered by three or more metal crossbeams. It is often found in prison cells and sewers. A grille is easier to spot (reduce Perception DC by -2) because there is a metal reinforced aperture in the floor for the bottom to snugly slot into, and that bottom consists of a metal crossbeam rather than spikes. This makes it impossible to lift or squeeze through. It also lends stability, increasing the DC to bend its bars by +2. A grille has 200 hit points. It is immune to all damage except acid, bludgeoning, and force.

Multiple Portcullises: Multiple portcullises drop down at strategic points throughout the location, not just in the immediate vicinity. This is usually done manually in an active and well-defended lair after an alarm is raised, rather than activated by a pressure plate.

Rusty Bars: If the portcullis is old, ill-maintained, or exposed to salt water or ocean wind, its bars may become rusty and the system that maintains it may be compromised for lack of lubricant, rusted chains, etc. In this case, the portcullis falls more slowly and loudly; The clang of its drop carries twice as far. Reduce the Dexterity saving throw to avoid being hit by DC 12. However, the rust on the bars causes any creature wounded by it to take 1d6 necrotic damage in addition to the usual bludgeoning and piercing damage.

Construction Time: Constructing this trap takes 2 weeks for new construction or 4 weeks to retrofit existing construction. It requires a small team of craftsmen plus an engineer, blacksmith, and stone-mason. This does not include a gatehouse with control room.

Cost: 250 gp for a standard interior portcullis or 500 gp for a standard exterior (or larger interior) portcullis. Double that cost for grilles, and triple it for blast doors. Add another 100 gp for fancy ornamental overhangs that help conceal the trap.

---

Pressed Flower

Source Game Master’s Guide to Traps & Terrors

Mechanical Trap

This trap consists of an ornate stone floor covered in depictions of beautiful flowers, often vibrant and bright with colors. Any colors are either painted on, or perhaps covered in worthless colored glass. However, some versions of the trap feature their flowers decorated with 1d4+1 x 100 pieces of quartz valued at 1 sp each, or semi-precious stones valued at 1 gp each.

Other versions may have magic aura cast over the flowers, and these petals might glow. If so, the trap radiates illusion magic.

Related Traps: Gas Chamber, Wall of Petrifying Poison Gas.

Trigger: Once 20 pounds or more of pressure is applied to any petal, all the petals immediately sink into the floor revealing rows of symmetrical holes placed along the center of the stonework.

Spot: A successful DC 15 Perception check by a creature within 5 feet of the trap reveals the petals might be pressure plates.

Disarm: Wedging an iron spike or other object under the pressure plate prevents the trap from activating. This requires a DC 15 Dexterity saving throw to succeed; if failed, the trap is triggered. If a save fails by 5 or more, the trap is triggered and the creature attempting to disarm it saves at disadvantage against its effects, unless it is an insect swarm. In that case, the swarm gains advantage on its first attack against the creature who failed to disarm it.

Dimensions: One flower (including its stem) fits in a 5-foot radius, so you can scale this trap up or down as you see fit, down to a minimum of a single 5 foot square. Each flower consists of a stem terminating in four petals, each revealing a single row of four Tiny holes once its pressure plates have been triggered.

Number of Uses: 1d4+1 before no more refills.

Reset: After 1 minute, the gas or spores cease to flow and the trap resets itself.

Effect: Any creature that enters the trap must make a DC 15 Dexterity saving throw not to step on one or more of the petals. Once triggered, this trap makes a hissing sound. Each flower floods a 20-foot wide, 20- foot tall cylinder full of gas, spores, or insect swarms (replace the hissing sound with buzzing or another appropriate sound if insects are released).

Nine sample effects are described below. Feel free to pick your favorite, or roll 1d10 on the table below: If multiple trap contents are rolled, this can result in insect swarms, gasses, and/or spores all going off at the same time (all coming from different flowers).

Blight Spores: Any creature caught in the trap’s area of effect must succeed on a DC 15 Constitution saving throw. If it fails, it takes 4d6+4 necrotic damage and suffers the poisoned condition. Every round after it has left the trap’s area of effect, the creature is allowed a new saving throw to negate the condition. If the saving throw succeeds, the creature takes half damage and is not poisoned.

Confusion Gas: Any creature caught in the trap’s area of effect must succeed on a DC 15 Wisdom saving throw. If it fails, it is affected as if by a confusion spell. If it succeeds, it is unaffected by the gas.

Fey Spores: The trap releases a cloud of spores gathered from the Feywild. The spores spread around corners. Any creature caught in the trap’s area of effect must succeed on a DC 15 Constitution saving throw. If it fails, it takes 4d6+4 psychic damage as it takes on an increasingly fey-like appearance (pointed ears, large eyes, delicate fingers and other physical features) over the next week. Its creature type changes to fey. If the save succeeds, it takes half damage as its body successfully fights off the physical changes. Every midnight after moving more than 1 mile from the trap’s location, a creature who failed its original saving throw is allowed a new one to return to its original form and creature type, but the DC increases by +1 per night. It is allowed one additional save per day equal to its Constitution modifier (minimum of 1). If all those saves fail, the physical changes become permanent.

d10	Pressed Flower Trap Contents
1	Insect Swarm
2	Confusion Gas
3	Poison Gas
4	Paralysis Gas
5	Sleep Gas
6	Blight Spores
7	Fey Spores
8	Fiend Spores
9	Shadow Spores
10	Roll 3x on this table, ignoring rolls of 10, and you can’t roll the same result more than once (roll again if this happens)

Fiend Spores: The trap releases a cloud of spores gathered from one or more Lower Planes, but usually all from within layers of the same plane (the Abyss, the Hells, Hades, etc.). The spores spread around corners. Any creature caught in the trap’s area of effect must succeed on a DC 15 Constitution saving throw. If it fails, it takes 4d6+4 psychic damage as it takes on an increasingly tiefling-like appearance (not including wings) over the next week. Its creature type changes to fiend. If the save succeeds, it takes half damage as its body successfully fights off the physical changes. Every midnight after moving more than 1 mile from the trap’s location, a creature who failed its original saving throw is allowed a new one to return to its original form and creature type, but the DC increases by +1 per night. It is allowed one additional save per day equal to its Constitution modifier (minimum of 1). If all those saves fail, the physical changes become permanent.

Insect Swarm: 1 insect swarm is released per flower. You choose the type, but wasps or other flying insects are the most commonly used. The swarm(s) attack all creatures (except constructs) present in the trap’s area of effect. If the creatures flee, the swarm(s) will relentlessly pursue them until they are blocked, killed, driven off, or otherwise defeated.

Paralysis Gas: Any creature caught in the trap’s area of effect must succeed on a DC 15 Constitution saving throw. If it fails, it suffers the paralyzed condition. Every round after that, the creature is allowed a new saving throw to negate the condition but is considered poisoned on the round the paralyzed effect is negated. If the saving throw succeeds, the creature is poisoned for 1 round but is not paralyzed.

Poison Gas: Any creature caught in the trap’s area of effect must succeed on a DC 15 Constitution saving throw. If it fails, it takes 4d6+4 poison damage and suffers the poisoned condition. Every round after it has left the trap’s area of effect, the creature is allowed a new saving throw to negate the condition. If the saving throw succeeds, the creature takes half damage and is not poisoned.

Shadow Spores: The trap releases a cloud of spores gathered from the Shadowfell. The spores spread around corners. Any creature caught in the trap’s area of effect must succeed on a DC 15 Constitution saving throw. If it fails, it takes 4d6+4 psychic damage as it takes on an increasingly pale, undead-like appearance over the next week. Its creature type changes to undead. If the save succeeds, it takes half damage as its body successfully fights off the physical changes. Every midnight after moving more than 1 mile from the trap’s location, a creature who failed its original saving throw is allowed a new one to return to its original form and creature type, but the DC increases by +1 per night. It is allowed one additional save per day equal to its Constitution modifier (minimum of 1). If all those saves fail, the physical changes become permanent.

Sleep Gas: Any creature caught in the trap’s area of effect must succeed on a DC 15 Constitution saving throw. If it fails, it is knocked out as if by a sleep spell. If it succeeds, it is poisoned for 1 round.

Options

To customize this trap, choose from the options below.

Sympathetic Magic: All conjuration, poison, and transmutation magic cast within 30 feet of this trap has its DC increased by +1 and deals an extra 1d4 poison dam-age on a failed save regardless of whether it normally deals poison damage or not. The trap itself does not benefit from this bonus unless the GM wishes it.

Construction Time: A trap of this complexity requires a highly skilled engineer, stonemason, and team of support artists and craftsmen to spend at least 1 week per flower (5-foot square). This includes digging the underground gas or spore reservoir and loading the canisters, testing, etc.

Cost: 1,000 gp per flower (5-foot square). Any colored glass, gems, or crystals are extra (see above).