Alien' ghost' sharks which live in the Midnight Zone of the ocean have been captured on film for the first time.
The sharks, and other types of fish, have gone undetected for millions of years after they made the deepest part of the sea their home.
The amazing ways they have had to adpt to where they live has been filmed for Discovery Channel's Most Bizarre Sharks of the Midnight Zone documentary.
It looks at the Gulper fish, whose eyes have been developing since the Jurassic period in order to find their prey in the depths of the dark ocean.
Their stomachs can expand massively so they can easily eat large prey.
An expert speaking on the documentary said: "In terms of light sensitivity a deep sea shark's eyes are better than the best camera out there.
"Light travels in through the cornea and is reflected back out, in order for the shark to essentially sees the image twice, so they can see under low light conditions."
The documentary also looks at the ghost shark, which it says has an otherworldly presence.
The expert added: "The ghost shark got its name because it looks like a ghost, it's got these big creepy eyes, it's got these big fins that drift off to the side and it floats around in the water in a very spooky fashion."
As well as looking like something out of a horror film, the strange sharks have a retractable sex organ on their heads.
The sharks are also knows as chimeras and live in the depths of the oceans where rays of sun will never reach.
It is believed they split up from their other shark cousins living closer to the surface of the sea around 30million years ago.