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Dragon Crab

Gargantuan monstrosity, neutral evil

Armor Class 18 (natural armor)
Hit Points 210 (12d20 + 84)
Speed 40 ft., swim 50 ft.

21 (+5) 13 (+1) 25 (+7) 17 (+3) 16 (+3) 11 (+0)

Saving Throws Constitution +12, Wisdom +8, Charisma +5
Skills Deception +5, Nature +8, Perception +8, Stealth +6, Survival +8
Damage Resistances bludgeoning from nonmagical weapons
Damage Immunities piercing and slashing from nonmagical weapons
Senses darkvision 120 ft., passive Perception 18
Languages Common and any four others
Challenge 16 (15,000 XP)

Special Traits


  • Multiattack. The dragon crab makes six attacks: two with its pincers and four with its legs. It can use Crush instead of a pincer attack.
  • Pincer. Melee Weapon Attack: +10 to hit, reach 15 ft., one target. Hit: 16 (2d10 + 5) bludgeoning damage. If the target is a Large or smaller creature, it is grappled (escape DC 15). The dragon crab has two pincers, each of which can grapple only one target.
  • Kick. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 12 (2d6 + 5) piercing damage.
  • Crush. Melee Weapon Attack: +10 to hit, reach 5 ft., one target grappled by the dragon crab. Hit: 16 (2d10 + 5) bludgeoning damage.

Legendary Actions

The dragon crab can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. The dragon crab regains spent legendary actions at the start of its turn.

  • Detect. The dragon crab makes a Wisdom (Perception) check.
  • Gleam. The dragon crab reflects light into the eyes of one target it can see within 60 feet. The target must succeed on a DC 18 Dexterity saving throw or be blinded until the end of the dragon crab’s next turn.
  • Pincer (Costs 2 Actions). The dragon crab performs two pincer attacks or uses Crush on up to two creatures it already has grappled.
  • Cast a Spell (Costs 3 Actions). The dragon crab casts a spell from its list of prepared spells, using a spell slot as normal.

Lair Actions

Dragon crabs lair in natural caves and grottoes in the ocean’s bed. The largest chamber of the lair will be crowded with the crab’s shimmering treasure hoard and crude cages containing dismembered corpses of victims who met their fates at the claws of the gigantic, sadistic enemy.

A bioluminescent algae cultivated by the crab grows upon some walls and ceilings, emitting a pleasant, polychromatic glow, and pockets of breathable air, the result of tidal forces and underwater currents, can be found within the network of natural caverns that comprise the lair.

On Initiative count 20 (losing initiative ties), the dragon crab can take a lair action to cause one of the following effects; it can’t use the same effect two rounds in a row:

  • Riptide. Pools of water within 120 feet of the dragon crab that it can see surge outward in a grasping tide. Any creature on the ground within 20 feet of such a pool must succeed on a DC 15 Strength saving throw or be pulled up to 20 feet into the water and knocked prone.
  • Pooling Shadow. Magical darkness spreads from a chosen point within 60 feet of the dragon crab, filling a 15-foot radius sphere until the dragon crab dismisses it as an action, uses this lair action again, or dies. The darkness spreads around corners. A creature with darkvision can’t see through this darkness, and nonmagical light can’t illuminate it. If any of the effect’s area overlaps with an area of light created by a spell of 2nd level or lower, the spell that created the light is dispelled.
  • Treacherous Hoards. A heap of the dragon crab’s treasure hoard collapses over one target within 120 feet that the dragon crab can see. The creature must succeed on a DC 15 Dexterity saving throw or take 10 (3d6) bludgeoning damage and be knocked prone and buried. The buried target is restrained and unable to breathe or stand up. The creature can take an action to make a DC 15 Strength check, ending the buried state on a success.

Regional Effects

The region containing a dragon crab’s lair is warped by the creature’s cursed presence, creating the following magical effects: Subservient Seas. The dragon crab can influence the behavior of aquatic creatures within 6 miles of the lair that have an intelligence score of 3 or lower, charming them, usually to lure them into the lair as food although they can be directed to swarm and attack creatures. If the dragon crab unbalances the local ecosystem through use of this power, the ability ceases to function for 1d20 months, until balance is restored. Most dragon crabs use this ability very sparingly.

Eldritch Tides. Surface waters in a 4-mile radius above the dragon crab’s lairs are prone to strange currents, unpredictable winds, and even some whirlpools. The dragon crab has no control over these and they cannot be used to its direct tactical advantage, but they increase the difficulty of seagoing navigation by 5 for any vessels or swimming creatures that attempt to traverse them. Local sea life has adapted to these strange currents; anything born within the 4-mile radius of the effect suffers no penalties in navigating it.


The pile of treasure shifts and slides away, revealing the form of an impossibly huge crab, its thick carapace studded with gold and gems. If the histories are accurate, a determined wizard decided to make himself an underwater army of gargantuan crabs to guard his island lair.

He succeeded in all but one respect. In granting the crabs the intelligence to understand and execute his orders, he accidentally made them both evil in outlook and far too intelligent to control. Communing with the sea in which they dwelt, the crabs taught one another to call forth the magics of nature itself and overthrew their creator, destroying his lair and scattering themselves throughout the sea. His later-discovered journals, history claims, reveal he originally created 3 dozen such crabs. Though they are unable to reproduce, rumor holds that nearly all have survived to this day, hidden in the deepest of underwater caverns, ruling the seas around them.

Dragon crabs tend to be greedy, both in carnivorous appetite and for treasure. Like some dragons, they often amass vast piles of gems, coins, and any other wealth that can survive at the bottom of the sea. Some also collect shipwrecks to decorate their lairs. Dragon crabs enjoy the pain of living creatures, especially intelligent ones, and often make a hobby of devising clever means to lure humanoids to their lairs to make them suffer for entertainment. Most dragon crabs harbor a strong dislike of wizards.

Though not universal, many dragon crabs line their shells with gaudy precious metals and stones, both for aesthetic reasons and to disguise themselves as piles of sunken treasure. Such crabs then bury themselves in loose sand and wait for unsuspecting adventurers to swim close and be ambushed. When not gem-encrusted, dragon crab shells are deep orange and grey, with patches of pale blue on the legs. They are about 60 feet in diameter, with pincers each as large as an elephant.

Section 15: Copyright Notice

Tome of Horrors © 2018, Frog God Games, LLC; Authors: Kevin Baase, Erica Balsley, John “Pexx” Barnhouse, Christopher Bishop, Casey Christofferson, Jim Collura, Andrea Costantini, Jayson ‘Rocky’ Gardner, Zach Glazar, Meghan Greene, Scott Greene, Lance Hawvermale, Travis Hawvermale, Ian S. Johnston, Bill Kenower, Patrick Lawinger, Rhiannon Louve, Ian McGarty, Edwin Nagy, James Patterson, Nathan Paul, Patrick N. Pilgrim, Clark Peterson, Anthony Pryor, Greg Ragland, Robert Schwalb, G. Scott Swift, Greg A. Vaughan, and Bill Webb