Stupendously rare footage of a bigfin squid, known for its alien-like appearance and unbelievably long tentacles, has been captured in the dark depths of the Pacific Ocean.

The video was recently shot by scientists from Minderoo-UWA Deep-Sea Research Centre and Inkfish as part of the ongoing Tonga Trench Expedition 2024. From July until October 2024, the voyage will use submersibles and deep-sea landers to map, profile, and survey the Tonga Trench, the second-deepest oceanic trench in the world after the Mariana Trench.

Their new footage of the bigfin squid was filmed at a depth of 3,300 meters (10,827 feet) using a deep-sea lander armed with a camera and a piece of fish for bait. 

It's the first time the squid has been seen in the Tonga Trench and the team considers themselves to be very lucky; fewer than 20 recorded sightings of the elusive creature have ever been made. 

Bigfin squid are known for their spindly tentacles that dangle from their bodies, stretching up to 8 meters (26 feet) in length. 

The unusual creatures belong to the genus Magnapinna, which means “great fin” in Latin. There are just three described species – M. atlantica, M. pacifica, and M. talismani – but it’s possible there are more out there in the ocean, as yet undiscovered. 

Professor Alan Jamieson, Director of the Minderoo-UWA Deep Sea Research Centre and leader of the current expedition, has previously published a paper on bigfin squid after coming in contact with one during a submersible dive in the Philippine Trench.

Along with documenting the marine life, the expedition is aiming to gather information about the geology of Horizon Deep, the deepest point of the Tonga Trench with a depth of approximately 10,800 (35,433 feet) below sea level.

Professor Jamieson recently ventured into the bowels of Horizon Deep onboard a crewed submersible and made a surprising observation: it appeared barren and gray, almost totally devoid of life except for a few scale worms. 

It’s not clear why biodiversity isn't found in abundance here, although it might have something to do with the stability of the sloped seabed.

“Absence is as interesting as presence, just perhaps slightly less immediately gratifying. It is fascinating why there is absolutely nothing here,” Jamieson said in a video explaining part of the Tonga Trench Expedition 2024.