The incredible footage – taken 930 metres below the surface of the water off Jarvis Island in the South Pacific Ocean – shows the crew of the E/V Nautilus zooming in on the mysterious-looking creature.
It has two distinct parts – a purple lower half that bears a resemblance to a traditional squid and then a top half that looks like some sort of underwater flower.
As they zoom in, the squid darts off camera and appears to turn red in the process.
“It’s like a unicorn,” one of the crew says.
The creature then comes back into view and tries to attack the vessel by opening up its tentacles.
Realising it would be a losing battle, the squid then squirts black ink before speeding off.
The amazing moment was captured on July 5, but the footage was only released on July 26.
It is believed to be the first time the asperoteuthis mangoldae squid has been filmed alive.
Dr. Michael Vecchione, from NOAA’s National Systematics Lab/National Museum of Natural History, said: “At first, it looked like a long, narrow squid with something stuck on it.
“The ‘something’ was actually part of the squid, a tail extending beyond the fins and effectively doubling the length of the animal.
“This was an Asperoteuthis mangoldae, a recently discovered deep-sea species that had never been seen alive until now.”
The unusual tail of the squid is believed to help it mimic other animals, namely a stinging siphonophore.
While the team were overjoyed to capture the extremely rare squid on camera, Dr Vecchione still has questions.
“If this is all about appearance, why is it important for survival in the almost lightless environment of the deep sea?” he asked.