Scuttler (5e Creature)
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Medium monstrosity, unaligned
Amphibious. The scuttler can breathe air and water.
Surprise Attack. If the scuttler surprises a creature and hits it with an attack during the first round of combat, the target takes an extra 10 (3d6) damage from the attack.
Multiattack. The scuttler makes two attacks with its claws.
Claw. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) bludgeoning damage, and the target is grappled (escape DC 13). The scuttler has two claws, each of which can grapple only one target. Miss: The scuttler can take the Disengage action as a bonus action and move up to 10 feet.
Scuttlers are curious aquatic predators that attack from ambush. Named for their odd scuttling movements, they lurk in shallows and primarily prey on land-dwelling creatures. If a scuttler's initial attack fails or combat turns against it, it flees, taking anything caught in its claws with it.
Territorial Crustaceans. Scuttlers usually hunt alone, but they gather in large groups and claim large patches of coast as territory. When an individual takes down prey, it drags it into the water and begins to feed, making a high-pitched sound that attracts other scuttlers to join the meal.
Great Scuttlers. Most scuttlers are about human-sized, but some are considerably larger and stronger. Often called great scuttlers, these oversized crustaceans are leaders among their kind, and have a strange influence over their lesser kin.