1. Frilled shark
2. Gulper eel
An eel with a mouth like a pelican. Little is known about this deep-sea monster, which lives around 3,000 metres below the surface and grows up to six feet long.
Why they are terrifying: Their weirdly enlarged jaws and super stretchy stomachs allow them to swallow prey as large as they are. Eek.
3. Fangtooth fish
4. Pacific viperfish
5. Humpback anglerfish
The anglerfish lives 2,000 metres below the surface and lures its prey with light, like the viperfish, but this time from a strange glowing antenna sticking out from its head.
Why they are terrifying: I mean, just look at it.
6. Stargazer fish
Stargazer fish bury themselves in the sand and wait for fish to swim right over them, at which point they spring out and eat them. They have a permanently upwards pointing head, perfectly adapted to this hunting technique.
Why they are terrifying: Just imagine looking down to the seabed and seeing that face.
7. Giant spider crab
8. Giant isopod
Giant isopods are like massive sea woodlice, and have been found in depths of up to 2,000 metres. They grow to around 30cm long, and are mainly scavengers but have also been known to catch live prey.
Why they are terrifying: These guys are the ultimate survivors. They have been around since all the continents were stuck together in one lump known as Pangea and they can go four years without eating, so really it's only a matter of time before they take over the earth.