Scary Jelly

Despite its size, Stygiomedusa is rarely caught on camera. In the 27 years that MBARI's ROVs have been patrolling the deep-sea, they've observed the strange animal just seven times.

"It's one of the largest invertebrate predators known in the ocean," says the team. "Yet little is understood about its ecology and behaviour."

Those long, draping structures you see in the video aren't stinging tentacles as you might imagine – they're "oral arms", masses of spongy tissue typically used for feeding. It's thought that the jellies use these arms to envelop unsuspecting prey (before you swear off the ocean forever, you should know that this behemoth eats plankton and small fish).

Despite its size, Stygiomedusa is rarely caught on camera. In the 27 years that MBARI's ROVs have been patrolling the deep-sea, they've observed the strange animal just seven times.

"It's one of the largest invertebrate predators known in the ocean," says the team. "Yet little is understood about its ecology and behaviour."

Those long, draping structures you see in the video aren't stinging tentacles as you might imagine – they're "oral arms", masses of spongy tissue typically used for feeding. It's thought that the jellies use these arms to envelop unsuspecting prey (before you swear off the ocean forever, you should know that this behemoth eats plankton and small fish).