Remarkable footage of a rarely seen giant deep sea jellyfish has been recorded by scientists off the coast of California.
The giant but elusive creature, which was first officially documented in 1899, has only been filmed nine times over the course of thousands of dives in Monterey Bay and officially spotted just 110 times in 110 years worldwide.
It lives anywhere from surface level to 21,900ft, but mostly sticks to an area called the twilight zone, which is too deep for most light to reach.
In the latest sighting, the mysterious phantom jellyfish was caught on camera by a deepwater robot at a depth of 3,200ft (990 metres).
The amazing footage was taken by researchers at the Monterey Bay Aquarium Research Institute (MBARI).
They managed to capture the deep sea creature, which has bizarre 33ft-long 'mouth arms' and is scientifically known as Stygiomedusa gigantea, from three different perspectives.
One angle shows the species' 3.3ft-wide (1m) bell pulsing as its four long tentacles undulate beneath it, while a shot from above makes the jellyfish look more like a hat.
A wider look reveals the reddish purple coloured creature's lengthy 'mouth arms', which scientists believe are used to grab and trap prey.
It is assumed they feed on plankton and small fishes, but very little is known about how the jellyfish survives.
Two sightings of it in the Gulf of Mexico suggest the species might hunt by clinging to subsea structures, so its arms are freed up to trap food, but that sort of behaviour has never been directly witnessed.
'Even now, scientists still know very little about this animal,' the research institute said.
'The challenges of accessing its deep-water habitat contribute to the relative scarcity of sightings for such a large and broadly distributed species.'
According to the scientists, giant phantom jellyfish appear to be in all oceans except for the Arctic.
Before underwater robots were invented, experts used trawling nets to study deep sea creatures such as Stygiomedusa gigantea.
However, when one is captured and brought to the surface, MBARI researchers said its silky-looking frame turns to 'gelatinous goo'.
That makes underwater robots the best way to observe the species and learn more about how it survives.
However, in 34 years of carrying out deep sea studies, MBARI has sent out thousands of remotely operated vehicles and observed the giant phantom jellyfish just nine times.
It is thought to be one of the largest invertebrate predators in the deep sea ecosystem.
Previous footage captured in 2004 also showed a fish swimming inside and in close proximity to the bell of the jellyfish.
It was even caught on camera resting its belly on the jellyfish.
The fish was believed to be Thalassobathia pelagica, a rare species itself that has a symbiotic relationship with the jellyfish.
By swimming within the jellyfish it is able to feed on scraps of food and have a certain level of protection in an otherwise shelterless abyss.
The research institute published the video on its website.