All the animals in Blue Planet II 'The Deep' ranked in order of freakiness ?

That giant squid. Brrrrrrrr.

(Image credit: BBC)

That giant squid. Brrrrrrrr.

Just when you think it couldn't get any more mind-bending, David Attenborough rolls out underwater brine lakes, giant cannibal squid and fish with see-through heads.

Blue Planet II The Deep took us down to the recently-explored depths of the ocean, where some of the most alien-looking animals thrive in pitch darkness.

We also saw the lengths it took a very brave camera crew to get shots of unrecorded life in the polar seas. As one Blue Planet II producer put it, 'There could be lots down there, there could be nothing down there - we just don't know.'

Here's (most of) what we saw, ranked by sheer freakiness.

The barreleye fish

Imagine being the first person to film one of these. Never mind the see-through forehead, look at its weirdly human fish-face??

Otherwise known as a 'spook fish', this rarely-filmed fish has a clear domed head with tubular eyes pointing upwards to help it spot predators from above, like a skylight but on its head.

(FYI there were no images available from last night's episode - presumably because the photographer dropped his camera in horror).

The contorting brine lake eel

Because every day of Blue Planet II is a school day, we also learned that whole lakes of brine exist under the sea, with their own shores covered in century-old mussels. WHAT. When a cutthroat eel dived into this brine lake looking for food, it went into a toxic shock that made its body twist and spin, The Exorcism Of Emily Rose-style. Brrrr.

The giant cannibal squids (and cockeyed squids - basically all the big squids)

One reason to never visit the Twilight Zone (other than being crushed to death by the water pressure): there are nightmarishly huge, 2-metre long squids down there that eat each other when they run out of food. In a close freaky second comes the cock-eyed squid, with its great green globe of an eye pointing up at us.

Whatever fresh devilry this is

The sea toad that has FEET

The zombie worms

Little worms that inject acid into the bones of a dead sperm whale to extract the remaining morsels of fat. Yummy...

The deep, deep, DEEP water snail-fish

No fish could survive at the bottom of the Mariana Trench, 8km below the surface, could it? But then this little ghost of a fish floated casually past a probe camera sent to the bottom. Minds blown.

The permanently startled-looking sixgill sharks

As big as Great Whites, but unlike Jaws they eat just once a year. I hate to be accused of fat-shaming a shark here, but these guys look like they ate last night.

The spider crabs with coral headpieces

Less freaky, more fabulous. You're OK where you are though, guys... No, seriously, back off.

Lucy Pavia