Here's a new one on me: a polychaete called the Bobbit worm, after the lady in the news a few years back who resolved her marital difficulties with scissors. The worm uses its shearing mouth parts merely to seize and kill prey. My correspondent Max, who shared the video below, compares this critter to the ones in the movie Tremors.
Bobbit Worm - Dinner time from liquidguru on Vimeo.
Apparently the Bobbit worm has on a couple of occasions showed up uninvited in aquariums. The news account linked below claims that the Bobbit, like a number of other worms in the class Polychaeta, has bristles loaded with a neurotoxic venom capable of harming humans.
Barry the giant sea worm discovered by aquarium staff after mysterious attacks on coral reef | Daily Mail Online: "We laid traps but they got ripped apart in the night. That worm must have obliterated the traps. The bait was full of hooks which he must have just digested.'"