Banded Claw. On one of its claws, the crab wears a rune-covered copper band that makes it immune to being charmed, frightened, and paralyzed. The copper band is worthless as a treasure, as the magic is keyed to this crab.
Amphibious. The crab can breathe air and water.
Claw. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit:27 (4d10 + 5) bludgeoning damage, and the target is grappled, escape DC 14. The crab has two claws, each of which can grapple only one target.