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. 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 mouthparts. It may also be found among coral reefs.
E. aphroditois is also known as the bobbit worm or bobbitt worm. The name is taken from the John and Lorena Bobbitt case. It is sometimes called the sand striker. Another name associated with them is trap-jaw worm, noted in 2021 to have been found among fossils near Taiwan dating back twenty million years.