Eunice aphroditois is a benthic bristle worm of warm marine waters. It lives mainly in the Atlantic Ocean, but can also be found in the Indo-Pacific. It ranges in length from less than 10 cm (4 in) to 3 m (10 ft). Its exoskeleton displays a wide range of colors, from black to purple and more. This species is an ambush predator; it hunts by burrowing its whole body in soft sediment on the ocean floor and waiting until its antennae detect prey. It then strikes with its sharp mandibles. It may also be found among coral reefs.

Eunice aphroditois is also known as the bobbit worm or bobbitt worm. The name is believed to be taken from the John and Lorena Bobbitt case. It is sometimes called the sand striker or trap-jaw worm. Traces of their burrows have been found among fossils near Taiwan dating back twenty million years.