Mysterious 'cosmic' jellyfish an undersea UFO

Underwater footage has captured one of the weirdest creatures in existence - a "cosmic" jellyfish that lurks in the ocean depths.

The film was taken by the US National Oceanic and Atmospheric Administration's Office of Ocean Exploration and Research on their first dive on the previously unexplored 'Utu' seamount, on February 21.

The intrepid researchers were using a remote-operated underwater vehicle when they came across the stunning creature.

cosmic jellyfish UFO
The jellyfish floating in the ocean (YouTube)

"You can see the yellow, likely reproductive organs," one of the scientists says in the video. "In the centre is the digestive system with the mouth in red. It's really amazing to see."

The jellyfish is in a family of hydromedusae called Rhopalonematidae, the scientists say.

"In this video, you can see the perfectly relaxed arrangement of the two sets of tentacles; scientists think this is a position that allows for optimum feeding in the midwater environment at ~3,000 metres."