Hazards

Hazards are typically non-sentient, passive challenges characters occasionally encounter and present some difficulty or hardship upon them unless successfully dealt with. Hazards include things like dangerous terrains, falling from tall heights, harsh weather, and more.

There are other challenges adventurers face, including curses, diseases, magical terrains, and more.

Hazards are grouped into a few different categories:

Visibility and Sensory Challenges

• Darkness & Obscurement

Natural Hazards

• Dehydration
• Exhaustion
• Falling
• Starvation
• Suffocation

Slimes, Molds, and Creature Hazards

• Green Slime
• Memory Moss
• Mold, Brown
• Mold, Yellow
• Muffle Moss
• Purple Moss
• Rot Grub

Environmental Hazards

• Corrosive Marsh
• Dust Flats
• Frozen Tundra
• Gaseous Waters
• Salt Deserts
• Scorched Plains
• Stormy Seas
• Volcanic Fields

Other Hazards

Hazards are not necessarily intentionally set to injure, harm, or delay creatures, but instead are usually naturally occurring phenomenon that do in fact either inconvenience or harm creatures. Hazards may include naturally collapsing ice or a wooden floor, or things like green slime or different types of molds that are sometimes found in subterrainean settings.

Antimagic Clouds

Source Legendary Adventures Epic 5e

Magical, Area-of-effect, Antimagic

Antimagic clouds have a radius of 6d10 feet (minimum 20 feet) and otherwise function as the antimagic field spell. At the end of every round, roll 1d20. On a 1–4, the antimagic cloud lingers in place. On a 5–19, the antimagic cloud moves 30 feet in the same direction as the last creature that exited it that round, or in a random direction. On a 20, roll again and ignore results of 20. The antimagic cloud sucks away magic until the end of the next round, removing a use from any magic item it touches that has more than a single use, and expending the highest level spell slot of any creature it touches.

Blighted Wilderness

Magicalcursed, necrotic, ground-based

Source Extreme Encounters Weather & Terrain for 5th Edition (5e) GMs Necrotic

This is an area of blighted ground created by the curse of a god or warlock patron, or a congregation of aberrations, the fey (usually hags), or undead, or the result of n altar or artifact installed and activated here. It is always gnarled, twisted, and dark; its thick canopy shuts out the sun.

Radiates: Conjuration and necromancy magic.

Area of Effect: Any, but usually confined to a lonely stretch of forest, jungle, swamp, or other wilderness far removed from civilization.

Expanded Area of Effect: If you wish to expand the area of effect beyond its original borders to threaten a wider area, simply expand it by 90 feet per minute (1 mile per hour). This terrain can only potentially expand a number of miles equal to the CR of the primary monster or villain, or up to 1 mile for an idol or relic.

Recognize Danger: Make a DC 10 Perception, Nature, or Survival check to recognize the transition from normal to difficult terrain. If you succeed, you may stop before entering.

Dispel Magic: This terrain cannot be dispelled.

Difficult Terrain: Creatures move at half-speed in this terrain due to the constant hazards of roots, thorns, vines, low-hanging branches, and undergrowth. If you move faster, you must succeed at a DC 15 Dexterity saving throw every round or else trip and take 1d4 bludgeoning damage, and be knocked prone. For every 30 minutes you spend in this terrain, you must succeed at a DC 13 Constitution saving throw or suffer 1 level of exhaustion from fighting the blight every step. Blighted creatures and those native to the blight ignore this penalty. To be considered “native,” a creature must have spent 3+ months living all or mostly inside this specific blighted wilderness.

Curse of the Blight: For every day a beast or humanoid spends in this terrain, it must succeed at a DC 13 Constitution save or be afflicted by the curse of the blight. Blighted creatures become twisted and deformed, covered in bark, moss, and fungus, and their alignment shifts one step closer toward evil. They gain a permanent barkskin but continue to lose 1 point of Charisma per day, becoming more hideous and tree-like.

As soon as their Charisma score drops to 0, they transform into an awakened tree if humanoid, or an awakened shrub if a beast.

Their alignment becomes chaotic evil. If you succeed at 3 saves over 3 consecutive days, you are immune to this blight’s curse, but not to any other blighted wilderness’s curse you encounter.

Blighted creatures cannot leave this terrain or they suffer 1 point of necrotic damage per round.

They also suffer 1 point of necrotic damage per round while exposed to nonmagical sunlight. The curse can be removed by remove curse (etc.) as long as the creature has not turned into a plant; if it has, only a greater restoration or heal can remove it.

Enchantment, Necromancy, Plant, Spore, and Thorn Magic: All enchantment, necromancy, plant, spore, and thorn-based magic (such as spike growth) has its DC increased by +2 and on a failed save, if it deals damage, it deals an extra 1d6 necrotic damage (regardless of whatever type it normally deals). In addition, the range of all such magic is doubled.

Double Trouble: Entangle, spike growth, wall of thorns, and similar spells that create plant, spore, thorn-based effects, and/or difficult terrain have their area of effect doubled.

Evocation and Radiant Magic: All evocation and radiant effects have their DC reduced by -2. In addition, range is halved. Any creature seen to be using these magics instantly becomes the primary target for blighted creatures to attack.

Dying of the Light: All magical fire and radiant effects have their bright and dim light reduced by half thanks to the thick, blighted canopy.

Tracking and Stealth: Tracking and Stealth rolls suffer disadvantage. Blighted creatures or those native to the blight gain advantage.

Boss Fight: The primary monster or villain can create and maintain both an entangle and spike growth in a 40 foot radius around itself (recharge 4-6); neither spell requires concentration to maintain (this includes the double trouble range bonus). Each needs a separate DC 15 saving throw to avoid. Living creatures that come within 20 feet of the primary monster or villain also suffer 1 point of necrotic damage per round (no save) from the cloud of necrotic spores circling around it like gnats. This damage is in addition to any similar abilities, traits, or powers the monster or villain has. Living creatures within 5 feet of it take 2 points of necrotic damage per round instead. Creatures with resistance to necrotic damage take no damage unless they come within 5 feet of it; at that point, they take 1 point of necrotic damage for each round they remain adjacent.

Terrain Anchor: If an altar, artifact, idol, or relic is causing the terrain, it has AC 10 and 120 hit points. It is immune to necrotic, poison, and psychic damage, and has resistance to all other damage types. It deals 4d4 necrotic damage per round to any non-attuned creature touching it. Any creature killed by it becomes an awakened tree if humanoid, or an awakened shrub if it was a beast (both become chaotic evil).

Duration: The terrain ends 1d12 hours after the primary monster or villain is driven out or destroyed, and/or the cause for the terrain is removed or destroyed (such as an idol or relic). If the primary monster or villain and/or cause for the terrain returns to the area, all terrain effects resume as before. However, the area of effect is reduced to half its original radius, centered on the primary monster, villain or cause. The area of effect increases by 10% per hour until it occupies its original radius.

Brown Mold

Source TM

Mold is usually hidden in decaying garbs, on a decomposing corpse, a chest, a tapestry covering a wormeaten wardrobe, etc.

Cursed Ground

Magical terrain, cursed, necrotic, ground-based

Source Extreme Encounters Weather & Terrain for 5th Edition (5e) GMs Necrotic

This area has been cursed by one or more gods, or a warlock patron, or a powerful necromancer (usually a lich). It is a broken, barren land where only weeds, vines, and thorn bushes grow. All other plant life is dead, gnarled, and twisted.

Beasts avoid this terrain at all costs and never pursue creatures inside, even when starving.

Radiates: Enchantment and necromancy magic.

Area of Effect: Any, but usually confined to a badlands or ruins containing undead creatures, and the curse extends to any locations beneath it.

Expanded Area of Effect: If you wish to expand the area of effect beyond its original borders to threaten a wider area, simply expand it by 90 feet per minute (1 mile per hour). This terrain can only potentially expand a number of miles equal to the CR of the primary monster or villain, or up to 1 mile for an idol or relic.

Recognize Danger: Make a DC 10 Arcana, Perception, or Religion check to recognize the transition from normal to difficult terrain. If you succeed, you may stop before entering.

Dispel Magic: This terrain cannot be dispelled.

Difficult Terrain: Living creatures move at halfspeed in this terrain due to the constant tripping hazards of broken stones, thorns, and vines. If you move faster, you must succeed at a DC 13 Dexterity save each round or trip and take 1d4 bludgeoning damage, and be knocked prone.

Cursed: For every 10 minutes you spend in this terrain, you must succeed at a DC 15 Wisdom saving throw or fall under the effects of a bestow curse as if cast by the primary monster or villain; roll a d4 to determine which effect you get from the four listed in the PHB for this spell. You cannot receive the same effect more than once, and after you have failed 4 saving throws, and have all the curses, you cannot be cursed by this terrain more than you already are. The curse lasts as long as you remain inside the terrain and for 1d4+1 days after you exit (or with remove curse).

Enchantment, Necromancy, and Thorn Magic: All enchantment, necromancy, and thornbased magic (such as spike growth) has its DC increased by +2 and deals an extra 1d6 damage of its type on a failed save. In addition, its range is doubled.

Evocation, Plant, and Radiant Magic: All evocation, plant, and radiant effects have their DC reduced by -2. In addition, range is halved.

Dying of the Light: All magical and nonmagical fire and radiant effects have their bright and dim light reduced by half thanks to the curse.

Tracking: Tracking rolls are mostly impossible here as any physical tracks (bloodstains, footprints, etc.) vanish 1d4+1 rounds later.

Boss Fight: Living creatures that come within 30 feet of the primary monster or villain must succeed at a DC 17 Wisdom saving throw or suffer a bane effect that does not require concentration for it to maintain. Living creatures allied with or otherwise friendly to the primary monster or villain are not affected by its bane. Any creature that comes within 10 feet of the primary monster or villain also suffers 1 point of necrotic damage per round (no save). This damage is in addition to any similar abilities, traits, or powers the monster or villain has. Living creatures within 5 feet of it take 2 points of necrotic damage per round instead. Creatures with resistance to necrotic damage take no damage unless they come within 5 feet of it; at that point, they take 1 point of necrotic damage for each round they remain adjacent.

Terrain Anchor: If an altar, artifact, idol, or relic is causing the terrain, it has AC 10 and 120 hit points. It is immune to cold, necrotic, poison, and psychic damage, and has resistance to all other damage types. It deals 4d4 necrotic damage per round to any non-attuned creature touching it. Any creature killed by it becomes a wraith if 5th level (or CR 5) and above, or a shadow if it was lower level or CR.

Duration: The terrain ends 1d12 hours after the primary monster or villain is driven out or destroyed, and/or the cause for the terrain is removed or destroyed (such as an idol or relic). If the primary monster or villain and/or cause for the terrain returns to the area, all terrain effects resume as before. However, the area of effect is reduced to half its original radius, centered on the primary monster, villain or cause. The area of effect increases by 10% per hour until it occupies its original radius.

Energy Cyclone

Source Legendary Adventures Epic 5e

These vicious weather anomalies are strong enough to rip people off the ground and they move with dangerous alacrity, speeding across a landscape and beyond the horizon. Energy cyclones have a radius of 4d100 feet (minimum 100 feet). At the end of every round, roll 1d20. On a 1, the energy cyclone lingers in place. On a 2–15, the energy cyclone moves 50 feet in a random direction. On a 16–20, the energy cyclone careens, moving at a rate of 100 feet in a random direction. Creatures inside of or in the path of a moving energy cyclone take 45 (10d8) randomly determined damage of a randomly determined type (1d8: 1—acid, 2—cold, 3—fire, 4—force, 5—lightning, 6—necrotic, 7—radiant, 8—thunder) and make a DC 20 Strength saving throw or are ripped off the ground and into the air, thrown 1d10 × 20 feet and landing prone at the start of the creature’s next turn. Objects not anchored to the ground receive no saving throw.

Fey Longings

Source Legendary Adventures Epic 5e

After any personal, intimate interaction with a fey, a creature must make a DC 20 Wisdom saving throw or contract this disease.

Fey aware of this danger can take special precautions to prevent it using wards made from special plants and oils and though most know this, few care.

Characters with fey ancestry (such as elves, gnomes, and half-elves) are immune.

It takes 1d4 days for the symptoms of fey longings to take hold. The infected creature begins to see fey wherever they look. At first it’s the giggling sound of pixies just behind the next tree, but after several days it’s not uncommon for the delusions to include being surrounded by thick vines, glistening psychedelic rains, or riding a colorfully-feathered frog (while in fact the infected creature might be tangled in ropes, showered in blood, or standing on swift-moving boat). While these vivid hallucinations are complete, they do not directly lead to a character being harmed or put into harm’s way.

When the infected creature makes an opposed Wisdom (Insight) check or a Charisma (Deception, Intimidation, or Persuasion) check, it must make a DC 18 Wisdom saving throw. On a failure, the character is charmed by one random creature it can see. This creature cannot be an ally of the infected creature. If there’s no viable target, the character instead has disadvantage on attack rolls and ability checks as it sees and tries to interact with a world beyond the veil.

The best cure for fey longings is to bring the infected creature to the Feywild to interact with its denizens and environment. At the end of each day spent in the Feywild, an infected creature makes a Charisma saving throw (DC 10 + 1 per previous save) to recover from the disease. Otherwise fey longing naturally fades after a month.

Fractured Rift Disorder

Source Legendary Adventures Epic 5e

Whenever a creature travels between planes using a naturally occurring portal or dangerous magical item (like a well of many worlds), it must make a DC 20 Constitution saving throw. On a failure, it is infected with fractured rift disorder.

Whenever the infected creature suffers a level of exhaustion, its connection to the Material Plane is tested. The character makes a DC 20 Constitution saving throw or is teleported 1d20 feet away in a random horizontal direction as its connection to the here and now shifts slightly.

Unless treated (see below) the rift continues to fracture and the infection worsens. At the end of every week during which a creature with a basic or mild infection does more than rest, it must make a Constitution saving throw (DC 18 + 2 per previous save). On a failure, the disease worsens. Consult Table: Fractured Rift Disorder. On a success, its infection reduces by one stage (from mild to basic, or basic to recovered).

All of this disease’s effects manifest only while on the Material Plane.

Restoration and similar magic have no effect on fractured rift disorder since the problem can’t be fixed with positive energy. Instead the infected creature needs to strengthen its connection to the world. Success on a DC 18 Intelligence (Nature) check diagnoses the disease and identifies a long-term treatment, usually requiring a month of peaceful meditation in an ancient grove or cave at the end of which the infected creature recovers.

Table: Fractured Rift Disorder

Fracture Level	Cumulative Effect	Worsens on…
Basic	Make a DC 18 Constitution save after taking a level of exhaustion, or teleport 1d20 feet in a random direction.	Failing a DC 20 Constitution saving throw at the end of a week of adventuring.
Mild	Make a DC 18 Constitution save after scoring or taking a critical hit, teleporting 1d20 feet in a random direction on a failure.	Failing a DC 20 Constitution saving throw at the end of a week of adventuring.
Severe	Become ethereal (as the blink spell) whenever the infected creature rolls a natural 1 on a d20. Make a DC 18 Dexterity save to avoid dropping held items just before the transition.	Automatically worsens after several weeks unless spent resting.
Deadly	When the infected creature has been targeted by a magical effect that changes its form or location within the last round and it makes a Strength check, melee attack roll, or attacks with a thrown weapon, it must succeed on a DC 18 Constitution saving throw or be transported to a random plane of existence.	–

Green Slime

Source TM

Green slime may hang from the ceiling, fall from half-eaten furniture, be concealed in large ceramic pots, a fountain or disguised as a potion in a chest, etc.

Lava

Source Legendary Adventures Epic 5e

A creature that touches lava takes 27 (5d10) fire damage. When a creature first enters into an area of lava or starts its turn there, it takes 55 (10d10) fire damage. A creature submerged in lava takes 110 (20d10) fire damage.

• Volcanic Fields. In particularly tumultuous regions magma can leap up out of fissures in the earth that form with little to no warning, spitting flaming death up into the air. Every 100 feet of travel in a Volcanic Field, roll 1d20. On a 20, the terrain rumbles and spits up lava from a point within 4d4 – 4 feet of a randomly determined creature. Each creature within 15 feet of the lava spout makes a DC 20 Dexterity saving throw or are hit by lava. A creature in the same square as the lava spout has disadvantage on this save. Alternatively, thermal geysers function in the same way but deal fire damage using d6s instead of d10s.

Kelpie’s Waters

Source The Ceaseless Caravan – Underground Oracle Publishing

Any fresh waters that the Kelpie claims as its home are teeming with thick overgrowth that is considered difficult terrain. A creature entering a Kelpie’s waters for the first time on a turn or starting its turn there must succeed on a DC 16 Dexterity saving throw or become restrained by the overgrowth within the waters. A restrained creature­ can use its action to try to escape, doing so with a successful DC 16 Strength (Athletics) or Dexterity (Acrobatics) check. Each 10-foot cube of overgrowth has AC 10, 15 hit points and immunity to bludgeoning, piercing, and psychic damage.

Lava Gout

Source: WG3

Non-magical, fire, earth

A random lava gout appears 100 feet from a PC. The flash of heat requires all creatures within 200 feet of it to succeed on a DC 11 Constitution saving throw, taking 11 (2d10) fire damage on a failed save or half as much on a successful one.

Also, for the next minute (10 rounds), large pieces of cooling lava rock fall from the sky within 200 ft. of the lava gout. A creature that begins its turn within this range must succeed on a DC 11 Dexterity saving throw, taking 7 (2d8) bludgeoning damage on a failed save or half as much on a successful one. Objects in range may also take this damage (GM’s discretion).

Pastrasite

Source Legendary Adventures Epic 5e

When a creature enters an area with pastrasites it must make a DC 20 Charisma saving throw as its psyche instinctively tries to maintain their personal timeline. On a success, the pastrasite immediately retreats, choosing another creature to infect until there are none at which point it can no longer maintain its temporal existence, disappearing and leaving behind a strong sense of imminence within would-be victims.

For the next hour these creatures have advantage on Intelligence checks made to recall information. On a failure, the creature is infected with the disease. The pastrasite immediately destroys several years of the infected creature’s past. If it has one, the character loses its background and gains a randomly determined background. This new background is now, and always has been, the infected creature’s past. The character is vaguely aware of what happened with blurred recollection of things being somehow ‘different’ than before becoming infected. Only spells that contact other planes can reveal information from the infected creature’s previous timeline. Most facts change as little as possible to remain consistent with the infected creature’s new past, but some friction remains. Whenever an inconsistency between the old and new timelines is first spoken of in front of the character, it takes 21 (6d6) psychic damage.

The new timeline gradually settles, and the true past can only be restored through powerful magic such as wish or miracle. Once a pastrasite has altered an infected creature’s timeline, although its effects remain the creature recovers from the disease. Spells like remove disease or features like a herald’s Lay on Hands have no effect on pastrasites.

Planar Bleed

Source Legendary Adventures Epic 5e

Whenever a creature casts a spell of 8th-level or higher within 1 round of the casting of another spell of 8th-level or higher within 100 feet, roll 1d20. On a 1, the magic bends reality so fiercely that it spawns a 1-foot diameter interplanar rip in space and time that lasts for 2d4 + 2 rounds. At the end of each round, the planar bleed moves 5 × 2d4 feet in a random direction.

At the start of its turn, a creature within 30 feet of a planar bleed makes a randomly determined saving throw (roll 1d6: 1—Strength, 2—Dexterity, 3—Constitution, 4—Intelligence, 5—Wisdom, 6— Charisma). On a failure, the creature is exposed to a randomly determined planar disease (roll 1d4: 1— fractured rift disorder, 2—fey longings, 3—pastrasite, 4—spectral thought-worms).

The planar bleed is stationary until someone controls it. If you are within 60 feet of an uncontrolled planar bleed, you can use an action to make a DC 25 Intelligence (Arcana) check. On a success, the planar bleed levitates in one direction of your choice, up to a number of feet equal to 5 × your Intelligence modifier (minimum 5 feet). On a failure, the sphere moves 30 feet toward you. If you attempt to control a planar bleed that is under another creature’s control, you make an Intelligence (Arcana) check contested by the other creature’s Intelligence (Arcana) check. The winner of the contest gains control of the sphere and can levitate it as normal.

Spectral Thought-Worms

Source Legendary Adventures Epic 5e

When a creature interacts with the Astral Plane (via the astral projection spell or magic item mishaps) without the protection of a mind blank spell, or when it suffers prolonged exposure to the less stable areas of the Astral Plane’s wild energies. Spectral thoughtworms can also be carried along a detect thoughts spell, telepathic connections, and similar effects. A creature exposed to a spectral thought-worm or an infected creature’s mind must make a DC 20 Charisma saving throw or contract the disease. In 1d4 days the spectral thought-worm’s symptoms manifest in an infected creature. The parasite infects the character’s mind and eats the infected creature’s identity, creating a mental space into which it will lay its eggs. An infected creature’s background characteristics start changing. Roll 1d4 to determine what changes (personality trait, ideal, bond, or flaw) then reroll the chosen characteristic.

This is the infected creature’s new belief structure, which the character might not notice on its own.

An infected creature that does not have these characteristics has its memories altered instead (as the modify memory spell).

When an infected creature finishes a long rest, it makes a DC 18 Charisma saving throw. On a success, the character’s mind fights against the spectral though-worm and in the resulting struggle one of its characteristics changes as above. On a failure, the worm clears enough space to lay eggs that hatch in 1d4 days. These start eating the infected creature’s personality, reducing its Charisma attribute by 1 until it reaches 0 and dies, at which point the spectral thought-worm escapes to the Astral Plane through the tiny planar opening created by the departing soul.

Spectral thought-worms are susceptible to psychic damage.

When an infected creature is targeted by lesser restoration, or takes psychic damage equal to or more than its Charisma score, the parasite goes dormant for a week.

A dormant spectral thought-worm is destroyed when the infected creature takes psychic damage equal to or more than its Charisma score. Upon destruction a spectral thought-worm dissolves into stray thoughts that are expelled throughout the next day as semi-insightful sayings that float through the character’s mind.

Sulfuric Steam

Source: WG3

Non-magical, fire, air, water

A geyser of steam rises violently out of the water nearby. Your nose and eyes sting instantly as the caustic vapors threaten to blind and suffocate you. A 10-foot-radius cloud of persistent and spreading sulfuric steam rises from the water within 30 feet of the party. Each creature requiring air must immediately make a DC 11 Constitution saving throw or be poisoned for 1d4 minutes.

The radius of the cloud grows by 10 feet each round until it reaches 60 feet in diameter at which point it disperses. Creatures requiring air to breathe who begin their turn in the area of the steam take 11 (2d10) acid damage. Additionally, the creature must succeed a DC 11 Constitution saving throw or be blinded until the end of their next turn. The cloud is not magical and can be dispersed and affected by spells that can move air.

Unholy Ground

Magical terrain, cursed, necrotic, ground-based

Source Extreme Encounters Weather & Terrain for 5th Edition (5e) GMs Necrotic

This unholy ground was desecrated by the loathsome work of a god, warlock patron, fiend, cult, or evil religion, or it could be the result of an altar, artifact, idol, or relic activated here.

Radiates: Abjuration and necromancy magic.

Area of Effect: Any, but usually confined to an cave complex, crypt, ruins, shrine, temple, or tomb containing fiends or undead.

Recognize Danger: Make a DC 13 Arcana, Perception, or Religion check to recognize the transition from normal to difficult terrain. If you succeed, you may stop before entering.

Dispel Magic: Refer to the Casting Dispel Magic Against Magical Terrain rules on page 5.

Difficult Terrain: Living creatures move at halfspeed in this terrain as its loathsome aura feeds off your life energy and fears. Fiends, undead, and creatures of any evil alignment are immune to it.

Expanded Area of Effect: If you wish to expand the area of effect beyond its original borders to threaten a wider area, simply expand it by 90 feet per minute (1 mile per hour). This terrain can only potentially expand a number of miles equal to the CR of the primary monster or villain, or up to 1 mile for an idol or relic.

Bastion of Evil: All non-evil creatures that enter this terrain must make a DC 15 Wisdom saving throw or be poisoned and unable to heal hit points by any means for 1d6 hours. In addition, for every 10 minutes non-evil creatures spend in this terrain, they must make a DC 15 Wisdom saving throw or suffer 1 level of exhaustion. Any creature that dies in this terrain rises as a wight if it had 5 or more levels or CR, or as a ghoul if it had less.

Enchantment and Necromancy Magic: All enchantment and necromancy cast by evilaligned creatures has its DC increased by +2 and deals an extra 1d6 damage of its type (psychic or necrotic) regardless of whether the saving throw is successful or not. In addition, its range is doubled.

Good Magic: All magic cast by non-evil aligned creatures has its DC reduced by -2. In addition, its range is halved.

Dying of the Light: All magical fire and radiant effects have their bright and dim light reduced by half thanks to the curse, and all nonmagical fires are immediately extinguished.

Tracking and Stealth: Tracking and Stealth rolls made by non-evil creatures suffer disadvantage. Evil-aligned creatures gain advantage instead.

Boss Fight: The first time non-evil creatures come within 30 feet of the primary monster or villain and who can see or hear it must succeed at a DC 15 Wisdom saving throw or give in to a telepathic command to grovel before it. Any non-evil creature that comes within 10 feet of the primary monster or villain also suffers 1 point of necrotic damage per round (no save). This damage is in addition to any similar abilities, traits, or powers the monster or villain has. Non-evil creatures within 5 feet of it take 2 points of necrotic damage per round instead. Non-evil creatures with resistance to necrotic damage take no damage unless they come within 5 feet of it; at that point, they take 1 point of necrotic damage for each round they remain adjacent.

Terrain Anchor: If an altar, artifact, idol, or relic is causing the terrain, it has AC 10 and 120 hit points. It is immune to cold, fire, necrotic, poison, and psychic damage, and has resistance to all other damage types. It deals 4d4 necrotic damage per round to any non-attuned creature touching it. Any creature killed by it becomes a wight if 5th level (or CR) and above, or a ghoul if it was lower level or CR.

Duration: The terrain ends 1d12 hours after the primary monster or villain is driven out or destroyed, and/or the cause for the terrain is removed or destroyed (such as an idol or relic). If the primary monster or villain and/or cause for the terrain returns to the area, all terrain effects resume as before. However, the area of effect is reduced to half its original radius, centered on the primary monster, villain or cause. The area of effect increases by 10% per hour until it occupies its original radius.

Whirlpool

Source Legendary Adventures Epic 5e

Innocuous eddies can suddenly whip up into powerful vortices that suck the party (or their vessel) beneath the waves! A whirlpool is stationary and appears to affect the water in a 50-foot radius, but grips upon creatures and objects in a 100-foot radius.

Staying on board a vessel in a whirlpool requires a DC 16 Strength check at the start of a creature’s turn.

At the end of each round, if a creature on the vessel has not succeeded on a DC 20 Dexterity (vehicle [water]) check it sails towards the whirlpool’s center at a rate of 30 feet each round; a successful check drives the vessel 15 feet away from the hazard.

Swimming away from whirlpool requires a DC 22 Strength (Athletics) check, and on a failure a creature is pulled 20 feet towards the whirlpool’s center. A vessel or creature drawn into a whirlpool’s center is sucked 20 × 4d10 feet down into the water and 50+5d6 feet away in a random direction.

Boiling Whirlpool

Source: WG3

Non-magical, fire, water

A 10-foot-radius whirlpool appears 60 feet from the party. Any creature that begins its turn in the water within 90 feet of the whirlpool must succeed a DC 11 Strength (Athletics) check or be drawn 20 feet toward it. Creatures swim at half speed while within 90 feet of the whirlpool. Objects such as boats or similar craft move 20 feet toward the whirlpool at the beginning of each round unless its operator succeeds a DC 11 skill check (GM’s discretion) Creatures who end their turn inside the whirlpool take 11 (2d10) fire damage.

Wild Magic Zone

Source Legendary Adventures Epic 5e

Wild magic zones are an unpredictable phenomena that vex even the greatest archmages, appearing without warning and disappearing after seemingly random periods of time—sometimes measured in seconds, sometimes minutes, sometimes months or even years. Perhaps the most upsettingly of all these anomalies cannot be heard, smelled, or seen, only detected after magic within its borders has gone haywire. All spells cast in a wild magic zone are automatically subjected to the effects listed on Table: Wild Magic Zones. Effects from a wild magic zone use randomly determined saving throws (roll 1d6: 1—Strength, 2—Dexterity, 3—Constitution, 4—Intelligence, 5—Wisdom, 6—Charisma). Roll twice for 8th-level spells, and three times for 9th-level spells.

Table: Wild Magic Zones

d20	Effect
1	The spell has no effect.
2	The spellcaster makes a randomly determined DC 20 saving throw or becomes blind and deaf for 1d4 rounds.
3	For the next minute, one randomly determined creature within 30 feet of the spellcaster can read its thoughts as the spell detect thoughts (DC 20).
4	The spellcaster’s size is reduced by one size category for 1 minute.
5	The spellcaster and every creature within 100 feet emanate a nimbus of energy that displays their alignments. This nimbus remains for 1 hour.
6	The spellcaster and every creature within 100 feet are teleported 15 feet to the nearest unoccupied space in a randomly determined direction (roll 1d8 for each creature).
7	The spellcaster and creatures within 100 feet grow a year’s worth of hair all at once (including creatures that do not naturally grow hair).
8	For the next minute, the spellcaster’s Speed is halved, its jump distances are halved, and it has advantage on Strength (Athletics) checks.
9	The spellcaster sheds deceptive bright light in a 10-foot radius and deceptive dim light for an additional 10 feet. The spellcaster and its allies are unable to see this deceptive light.
10	For the next round, the spellcaster and every creature within 100 feet benefits as if they had cast the detect thoughts spell without the need for concentration, and each can take an additional action on their turn. This action can only be used to focus on detect thoughts.
11	For the next round, the spellcaster and every creature within 50 feet benefits as if they had cast a randomly determined spell without the need for concentration (1d4: 1—displacement, 2—fly, 3—haste, 4—stoneskin).
12	Ethereal butterflies burst into existence in a 20-foot-radius sphere around the spellcaster and flutter for 1 minute. The sphere spreads around corners, and its area is heavily obscured.
13	For the next minute, the spellcaster’s Speed is doubled, its jump distances are doubled, and it has advantage on Dexterity (Acrobatics) checks.
14	The spellcaster and creatures within 100 feet lose all the hair on their bodies.
15	Time seems to slow down for the spellcaster and every creature within 50 feet, and until the start of the spellcaster’s next turn each reduces its Speed by half.
16	The spellcaster and creatures within 50 feet bleed shadows that make each lightly obscured for the next minute.
17	The spellcaster’s size is increased by one size category for 1 minute.
18	For the next minute, the spellcaster can read thoughts as the spell detect thoughts (DC 20).
19	The spellcaster’s senses are enhanced for 1 minute. Roll 1d4: 1—advantage on Wisdom (Perception) checks, 2—gains darkvision 60 feet (or increases darkvision range by 30 feet), 3—gains tremorsense 30 feet, 4—gains blindsight 20 feet.
20	The spellcaster regains the spell slot used to cast the spell.

Yellow Mold

Source TM

Mold is usually hidden in decaying garbs, on a decomposing corpse, a chest, a tapestry covering a worm-eaten wardrobe, etc.