Mesmerizing footage reveals a swimming sea slug like never before, which feeds using a large jelly-like hood and glows to defend itself from predators.

Living between 3,300 and 13,100 feet deep (1,000 to 4,000 meters), the mysterious mollusk (Bathydevius caudactylus) is the first species of nudibranch found living in the deep water column. Researchers first captured images of the animal in February 2000 using a remotely operated vehicle (ROV) off the coast of Monterey Bay. They spent the next 20 years learning more and gathering enough information to publish the most comprehensive description of a deep-sea animal to date.