Giant Phantom Jellyfish Filmed Off Argentina Stuns Scientists

On February 4, 2026, a team of scientists working with the Schmidt Ocean Institute made a discovery that left even seasoned marine biologists speechless: a rare giant phantom jellyfish, Stygiomedusa gigantea, was caught on camera drifting through the deep waters off the coast of Argentina. The footage, recorded by the Institute’s remotely operated vehicle (ROV) SuBastian, captured the elusive creature gliding 820 feet beneath the surface in the Colorado-Rawson submarine canyon wall, its ribbon-like tendrils undulating in the darkness like something out of a dream—or perhaps a deep-sea nightmare.

The sight was nothing short of extraordinary. According to the Schmidt Ocean Institute, the jellyfish is capable of growing to the length of a school bus—up to 33 feet long, with a bell that can stretch more than three feet across. In the mesmerizing video, the jellyfish’s pink, trailing arms seem to cascade endlessly through the water, providing a surreal spectacle for both the scientists and anyone lucky enough to view the footage. The Institute noted that these tendrils, though imposing, lack stingers. Instead, the jellyfish uses its four long arms to ensnare prey, guiding small fish and plankton towards its mouth. As the video rolled, young fish could be seen swimming alongside the jelly’s billowing ribbons, undisturbed by any threat of a sting.

The expedition, led by Argentinian scientists and spanning the entire length of the country’s coastline from Buenos Aires to the frigid waters offshore from Tierra del Fuego, was about much more than just one remarkable jellyfish. The research team, aboard the R/V Falkor (too), set out to explore Argentina’s continental shelf, hoping to uncover the secrets of its deep-sea ecosystems. Their findings, as it turns out, exceeded even their own expectations.

"We were not expecting to see this level of biodiversity in the Argentine deep sea, and are so excited to see it teeming with life," said Dr. María Emilia Bravo, a marine biologist with the University of Buenos Aires and the expedition’s chief scientist, in a statement reported by FOX Weather and WJW. "Seeing all the biodiversity, ecosystem functions, and connectivity unfolding together was incredible. We opened a window into our country’s biodiversity only to find there are so many more windows left to be opened."

Among the team’s most impressive discoveries was the largest-known Bathelia candida coral reef in the world, a vibrant underwater structure covering 0.4 square kilometers—roughly the size of Vatican City, as highlighted by the Schmidt Ocean Institute. This stony coral provides a critical habitat for countless species, including octopuses, fish, and crustaceans, making it an indicator of the region’s ecological health. Even more astonishing, the researchers found reefs of Bathelia further south than ever previously recorded, expanding scientists’ understanding of the coral’s range and resilience.

The team’s journey along the Argentinian coast yielded a trove of new life. In total, they documented 28 suspected new species, ranging from worms and anemones to sea snails and corals. As noted by the Schmidt Ocean Institute and reported by Storyful, these discoveries represent a significant leap forward in cataloging the region’s marine biodiversity.

But the surprises didn’t end there. The expedition also uncovered a cold seep—a rare area where gases and chemicals are released from the seafloor, fueling unique microbial communities and supporting creatures like clams, mussels, and tube worms. This cold seep, measuring over one square kilometer, was more than double the size of the massive coral reef nearby. The team even witnessed Argentina’s first deep-water whale fall, a dramatic event where a whale carcass settles on the ocean floor, creating a temporary ecosystem for a host of scavengers including octopuses, sharks, and crabs. Such whale falls are seldom observed and provide invaluable insight into the cycles of life and death in the deep sea.

Collecting data at these depths is no small feat. The Schmidt Ocean Institute’s ROV SuBastian proved invaluable, allowing researchers to capture high-definition video and collect samples from places where sunlight never reaches. According to Dr. Melisa Fernández Severini of Instituto Argentino de Oceanografía and CONICET, the team gathered “an unprecedented number of chemical, physical, and biological samples that will be used to understand connections in our waters for years to come.” She emphasized, “These samples represent a unique opportunity to understand not only how extraordinary these extreme ecosystems are, but also how vulnerable they can be.”

Yet, as awe-inspiring as the discoveries were, the expedition also highlighted the fragility of these remote habitats. The researchers found garbage and plastic fishing nets littering the seafloor, even stumbling across a VHS tape with a Korean sticker—a stark reminder of how far-reaching human impact on the oceans can be. The presence of such debris, thousands of miles from its likely origin, raises uncomfortable questions about the global problem of marine pollution and the urgent need for international cooperation to protect these vital ecosystems.

"With every expedition to the deep sea, we find the ocean is full of life—as much as we see on land, and perhaps more because the ocean contains 98 percent of the living space on this planet," said Dr. Jyotika Virmani, executive director of the Schmidt Ocean Institute. She added, “We have been privileged to work with outstanding scientists across three expeditions in Argentinian waters, and look forward to seeing their research continue to unfold, unlocking new understanding and inspiration.”

As the world takes in the breathtaking images of the giant phantom jellyfish—its ghostly form drifting through the blue—scientists are left with both a sense of wonder and a renewed sense of responsibility. The deep sea, it seems, is teeming with life, mystery, and fragile beauty, much of it still waiting to be discovered. The work of the Schmidt Ocean Institute and its partners is a reminder that while the ocean’s depths may be out of sight, they are never out of mind for those determined to explore, understand, and protect them.