Crab Swarm
A writhing mass of clacking shells and snapping pincers rushes from the surf, their spider-like legs twitching across the sand.

Crab Swarm (CR 4; XP 1,200)
N Diminutive vermin (aquatic, swarm)
Init +2; Senses darkvision 60 ft.; Perception +0
Defense
AC 18, touch 16, flat-footed 16
(+2 Dex, +2 natural, +4 size)
hp 38 (7d8+7)
Fort +6, Ref +4, Will +2
Immune mind-affecting effects, swarm traits, weapon damage
Offense
Speed 30 ft., swim 20 ft.
Melee swarm (2d6)
Space 10 ft.; Reach 0 ft.
Special Attacks distraction (F-DC 14)
Statistics
Str 1, Dex 14, Con 13, Int —, Wis 10, Cha 2
Base Atk +5; CMB —; CMD
Skills Swim +10; Racial Modifiers uses Dex to modify Swim
Ecology
Environment aquatic
Organization solitary, pair, or wave (3–8 swarms)
Treasure none

Crab swarms contain over a thousand normal-sized crabs that rush over their victims, plucking flesh with thousands of pinching claws. Some fishermen claim tides and phases of the moon cause these creatures to swarm as they do.