Gods, that's a big lobster. Except it isn't, and it's probably going to kill you. Chuuls like to hang out in shallow waters, just below the surface, waiting for idiots to wander by. With massive, crab-like claws, it can easily snap things apart — but the real danger tends to be its paralytic tentacles, that lash out and inject a necrosis like poison. Gross. Crabs are gross. Instinct: Devour intelligent prey

• Crush prey between claws
• Paralyze prey with tentacles

Imagine the hulking Leviathan, tearing ships apart and pulling sailors into the depths, to feed on them later. Imagine the power such a creature would have, and the destruction it could cause when it brought its full power to bear. Except it's not quite grown up yet. So it sinks small fishing ships, feeds on the bodies of old sailors that aren't fast or strong enough to fight, and generally tries to destroy anyone who comes into its waters. It's going to get big and REALLY strong... just not today. Instinct: to destroy any that enter its waters

• Pull people into the depths
• Throw people from ships
• Damage hulls