This is the Eunice aphroditois, a worm found in the depths of warm ocean waters across the world. It lives at depths of about 10 to 40 meters. The Eunice aphroditois burrows into the ocean floor, where it lies in wait for prey to swim by. Five antennas poke out from the anterior, sensing passing movement.
When the worm detects prey--a fish or another worm--it leaps from its burrow, seizing the prey with sharp mandibles.
Most of these worms are about 1 meter long, but they have been found as long as 3 meters. Although they can't consume an entire human body, they have been known to bite as people who stray too close.
(Photo: Jenny Huang)
-via io9