Exoskeleton, Giant Crab

Exoskeleton, Giant Crab

What looks at first like a Giant crab being ridden by a cloaked humanoid turns out to be only the former beast’s exoskeleton, hollowed out and magically animated to become both a vehicle and a war machine.

Giant Crab Exoskeleton

XP 700 ()

Unaligned Large

Initiative +0


AC 18 (natural armor)

hp: 57 (6d12 + 18)

Resistance: Piercing and slashing damage; necrotic damage

Immunity: Lightning, poison, and psychic damage; charm, disease, exhaustion, fright, poison, stun, unconsciousness


Speed: 20 ft., swim 20 ft.

Multiattack: A Giant crab exoskeleton attacks twice with claws or once with lightning.

Melee Attack—Claw: +7 to hit (reach 10 ft.; one creature). Hit: 1d8 + 5 slashing damage plus 1d8 lightning damage.

Area Attack—Lightning (recharge 5, 6): automatic hit (range 30-ft. line; all creatures in line). Hit: 3d8 + 3 lightning damage, or half damage with a successful DC 13 Dex saving throw.


Str 20 (+5), Dex 10 (+0), Con 16 (+3),

Int 1 (–5), Wis 10 (+0), Cha 4 (–3)

Languages: None

Senses: Darkvision 60 ft.


Lightning Insides: Whenever a Giant crab exoskeleton takes slashing or piercing damage, lightning from its insides erupts through the wound and ripples across its entire body. Every creature within 5 feet of the Giant crab exoskeleton must make a successful DC 13 Dex saving throw or take 1d8 lightning damage. Anyone riding inside the creature is immune to this damage.



Organization: Solitary, team (1–3), or caravan (2–12)

Giant crab exoskeletons are animated by little-known necromantic spells cast on only the largest Giant crab shells (10-foot diameter is typical; huge crab exoskeletons of 15-foot diameter are reported but unconfirmed). The process also involves etching magical runes onto the dead creature’s husk which give them great staying power in the face of clerics who would turn them as undead. These same runes give Giant beetle exoskeletons resistance to all piercing and slashing damage, including that from magical weapons.

In rare cases, the necromancer responsible for creating one of these creatures altered the process so that only the head of the exoskeleton filled with lightning while most of the body remained empty. The empty portion could then be fitted with seats for up to four people to use as a slow-moving vehicle. In ages past, at least one entire tribe of necromancers was known to migrate up and down the coast in such conveyances. Occasionally one of these Giant crab exoskeletons is discovered in a tidal cave, abandoned but still perfectly functional after centuries of disuse and ready to resume duty—if a way can be found to take control of it.