A team aboard a research vessel could barely contain themselves recently when a shapeshifting jellyfish emerged from the depths to put on a ghostly display in front of their remotely operated vehicle (ROV). 

The undulating jelly was spotted more than 2,500 feet (762 metres) below the central Pacific Ocean by researchers working for the Ocean Exploration Trust. The team initially compared the animal to a ghost character from the classic 80s arcade game Pacman, but the jelly soon proved that it was far more versatile than that.

The deep-sea creature quickly began morphing into a formless blob revealing a small, red isopod hitchhiking beneath its sheet-like folds. The isopod, a type of segmented crustacean related to deep-sea pillbugs, is probably not being preyed on, but "it is likely that this small crustacean consumes pieces of jelly while remaining hidden from predators," the Ocean Exploration Trust explains in a blog post, adding that the relationship between the two is not yet fully understood.

The jellyfish belongs to the genus Deepstaria and is a relative of the even stranger D. enigmatica, a species only seen a handful of times. Unlike other jellyfish, these ghostly creatures do not have stinging tentacles, so scientists are not entirely sure how Deepstaria eat. It's thought that they are filter feeders, trapping prey inside their expansive bag-like bell. A geometric mesh pattern serves as a network of canals along which food can travel to the stomach at the top of the bell. "As the jelly can reach a large size when inflated, these channels help distribute nutrients across the entire expanse," the team explain online.

The Nautilus research vessel is currently exploring the Pacific Remote Islands Marine National Monument, an expansive marine protected area spanning 490,343 square miles (1,269,979 square kilometres) in the central Pacific Ocean. The team are collecting deepwater baseline information to support science and management decisions in the area. For more updates from the almost-always fascinating ocean depths, visit the Nautilus website.