Bruce Robison was sitting in the control room of a research ship in Monterey Bay when he first saw the diaphanous deep-sea creature glide across a video screen. He had no idea what it could possibly be.

A "remarkable" new sea slug nicknamed the “mystery mollusk” has been discovered swimming deep in the ocean's "midnight" zone. The species has "unique" adaptations for life in the pitch-black depths including a large gelatinous hood to trap prey,

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.

Researchers have discovered an unlikely new species within the ocean's midnight zone: a glowing "mystery mollusk."

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,