Amphibious (The crab can breathe air and water.) Helmet Shell (The crab wears a metal carapace as a shell. If it is damaged in any way, it loses the helmet and its Armor Class becomes 15.)
Claw (melee weapon atk: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) bludgeon dmg, and the target is grappled (escape DC 11). The crab has two claws, each of which can grapple one target.)