Scientists from the Schmidt Ocean Institute recently spotted a giant phantom jellyfish (Stygiomedusa gigantea) 830 feet below the surface of the Pacific Ocean.
The jellyfish was encountered by a Remotely Operated Vehicle (ROV) that was exploring the Colorado-Rawson submarine canyon wall off the coast of Argentina. Prior to the days of underwater robots, however, researchers used trawling nets to study deep-sea creatures.
The phantom jelly is very rare, with only approximately 118 sightings recorded over 110 years. And of those sightings, even fewer have been recorded as these jellyfish have only been captured on film about a dozen times.
The creatures are believed to be spread out throughout the world’s oceans, except in the Arctic Ocean. The giant phantom jellyfish has four long oral arms that don’t sting, unlike the tentacles of its smaller jellyfish counterparts. Researchers have assumed that the appendages are instead used to grab prey and bring it to their mouths, but that behavior hasn’t been observed.
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Thought to be one of the largest invertebrate predators in the deep-sea ecosystem, it’s assumed that the creatures feed on small fish and plankton to survive. They’re also capable of reaching lengths of 3.3 feet across and 33 feet long, according to the Monterey Bay Aquarium Research Institute (MBARI) in California.
ROV pilots filmed this giant phantom jelly, or Stygiomedusa gigantea, at 253 meters during an ROV descent to explore the Colorado-Rawson submarine canyon wall. #ArgentinianDeepSeeps pic.twitter.com/80tq5JYOTz
— Schmidt Ocean (@SchmidtOcean) January 2, 2026
A fish was previously spotted swimming alongside a giant phantom jelly by MBARI’s ROV Tiburon during an expedition to the Gulf of California. The fish hovered near the jellyfish, swimming in and out of its arms.
Though the jellyfish lives anywhere from surface level to 21,900 ft deep, it mostly resides in the Midnight Zone or Twilight Zone, which is about 3,300 to 13,100 feet deep. As the waters in the Twilight Zone don’t offer much shelter, fish at this depth sometimes find shelter in other animals, like the jellyfish residing there.
