The Bobbitworm is an acquatic polychaete worm, found in warmer oceans - such as the Indo-Pacific and Atlantic. He generally lives in tunnels beneath the ocean floor. Here he lurks, waiting for his prey to come close. When something - ie: a fish - brushes against one of his five antennae he strikes with devastating speed and can actually chop his prey in half. If that is not enough, he also injects a narcotizing or killing toxin into the victim, so that it can be safely ingested, especially important if the prey is larger than his gut. He can grow up to 3 metres long - although most measure around 1m - but is only an inch or so in diameter.
Here’s a Bobbitworm in action: