With only 114 sightings in the last 110 years it is a jellyfish that is rarely seen, but believed to be widespread throughout the world. It is thought to be one of the largest invertebrate predators in the deep sea ecosystem. The jellyfish has an umbrella-shaped bell that can be up to a metre wide, and has four arms that extend up to six metres in length. These “paddle-like” arms lack stinging tentacles, and scientists are unsure of their exact function. It has been suggested that they might be used to envelop and trap prey.
On May 19, 2009 scientists filmed a giant Stygiomedusa in its natural deep sea habitat for the first time. Direct observations of these creatures from submersibles are very rare. It has been previously videoed by scientists off the Pacific coast of the US and by ROVs off Japan. However, this is the first time the giant jelly has been recorded in the Gulf of Mexico.