This ghostly giant is a rare sight. But in November 2021, MBARI researchers spotted this giant phantom jelly (Stygiomedusa gigantea) with the ROV Doc Ricketts 990 meters (3,200 feet) deep in Monterey Bay. The bell of this deep-sea denizen is more than one meter (3.3 feet) across and trails four ribbon-like oral (or mouth) arms that can grow more than 10 meters (33 feet) in length. MBARI’s ROVs have logged thousands of dives, yet we have only seen this spectacular species nine times.

The giant phantom jelly was first collected in 1899. Since then, scientists have only encountered this animal about 100 times. It appears to have a worldwide distribution and has been recorded in all ocean basins except for the Arctic. The challenges of accessing its deep-water habitat contribute to the relative scarcity of sightings for such a large and broadly distributed species.

Historically, scientists relied on trawl nets to study deep-sea animals. These nets can be effective for studying hardy animals such as fishes, crustaceans, and squids, but jellies turn to gelatinous goo in trawl nets. The cameras on MBARI’s ROVs have allowed MBARI researchers to study these animals intact in their natural environment. High-definition—and now 4K—video of the giant phantom jelly captures stunning details about the animal’s appearance and behaviors that scientists would not have been able to see with a trawl-caught specimen.