Giant Phantom Jellyfish Spotted off Argentina with 33-Foot Tentacles — Watch Video

Marine scientists have captured rare, high-definition footage of a Giant Phantom Jellyfish (Stygiomedusa gigantea) in the deep waters off Argentina’s coast. The colossal jellyfish, estimated to be the size of a school bus, was observed by a Remotely Operated Vehicle (ROV) at a depth of several thousand feet. This sighting is especially significant, as the species has been recorded fewer than 150 times since its discovery in 1899.

The video shows the jellyfish drifting through the “midnight zone,” a part of the ocean devoid of sunlight. The creature features a deep reddish-purple bell over three feet wide and four ribbon-like oral arms extending up to 33 feet. Unlike typical jellyfish, it lacks stinging tentacles, instead using its massive, scarf-like arms to trap and consume prey.

The ‘Phantom’ of the Deep Sea

The Stygiomedusa gigantea is among the largest invertebrate predators in the deep-sea ecosystem. Its nickname, the “Phantom Jellyfish,” comes from its elusive nature and the way its translucent, velvety arms flow with ocean currents. Living at depths between 3,000 and 20,000 feet, observing its natural behavior remains extremely challenging for scientists.

Researchers noted the jellyfish moved with a slow, pulsing motion, using its large surface area to navigate the high-pressure environment of the South Atlantic.

Technological Breakthroughs in Marine Research

The discovery was enabled by advanced underwater robotics capable of withstanding the deep ocean’s crushing pressure. The ROV used 4K cameras and specialized lighting to document the jellyfish without disturbing it.

“Every sighting of a Phantom Jellyfish provides critical data on the biodiversity of our oceans,” said one lead researcher. “Seeing a specimen of this size and in such pristine condition helps us understand how these apex gelatinous predators survive in the resource-scarce deep sea.”

While little is known about its lifespan or reproduction, scientists believe the Giant Phantom Jellyfish plays a key role in the deep-sea food web. Previous observations suggest small fish use its bell for shelter, hinting at a symbiotic relationship where the jellyfish offers protection in exchange for food scraps or cleaning services.