An unusual sea slug with a large hood, a tail with fingerlike projections and glowing bioluminescence has been found living off the West Coast of the US.

According to Bruce Robison, a senior scientist at the Monterey Bay Aquarium Research Institute, it’s “the most comprehensive description of a deep-sea animal ever made.” The team published its description in Deep-Sea Research Part I and comes on the heels of over 150 additional sightings of the creature by MBARI ROVs.

One of the weirdest sea slugs known to science has been discovered at a staggering depth, swimming around right down in the Midnight Zone between 1,013 to 4,009 meters (3,323 to 13,153 feet). As well as becoming the first sea slug known to live in the deep-water column,