Bobbit Worms come from warm, shallow waters in the Indo-Pacific area. Average adult length seems to be around 1 metre (3.3 feet), but it's said that some individuals have been found to be some 3 metres (9.8 ft) long!
They're ambush predators, spending their time in burrows with their head emerging from the sand and awaiting an opportunity to be vicious and deadly.
This opportunity is sensed using 3 antennae and 2 palps that point up from the head. They also have a pair of eyes but they don't seem to be so useful.
When a hapless fish approaches the burrow, the Bobbit attacks. Lunging with astonishing and rather unwormlike speed, the Bobbit shuts its powerful, serrated jaws with such force that victims are sometimes sliced in half. I bet the Bobbit is all "whoops, LOL!" when that happens.
And yet these worms aren't entirely carnivorous. At night they will sometimes investigate their surroundings, crawling around on their side-bristles in search of seaweed and the like to eat. If this miniature tower of malice can eat his greens for a bedtime snack, then there's hope for us all!