Meet 30 Deep-Sea Creatures So Weird They Should Be Aliens

First up: a sea slug that totally baffled scientists when they saw it. It has a big hood on one end, a tail with finger-like bits on the other, and it’s colorful inside. They called it the “mystery mollusc” because, well, it was a mystery! Turns out, it’s the only sea slug known to swim around deep in open water, not just hang out on the seafloor.

Meet the flapjack octopus - basically a fluffy orange pancake with arms that flap! When it spots danger, it swims away by flapping fins, waving arms, and using jet power all at once. Then, just like a parachute, it floats right back down to the sea floor.

The strawberry squid has one big eye and one smaller eye - and it's a perfect combo! The big eye looks up to spot shadows, and the small eye looks down to catch glowing flashes. Plus, its red color hides it perfectly in the deep dark.

Here's a mom with serious patience. She guards her eggs on the seafloor for over four years - yes, years! She doesn’t leave her post, slowly loses weight, and then... poof! The babies hatch and she’s done. Ultimate mom move right there.

The deep-sea crown jelly is a party animal with a long glowing tentacle to snag snacks and a flashing light show to scare off trouble. It’s like the disco queen of the deep!

Despite the spooky name, the vampire squid loves to chill and snack on 'marine snow' (aka ocean drift leftovers). When freaked out, it flips inside out to show off spooky spikes and shoots glowing ink to make a quick getaway.

Meet the ultimate fisherman with a built-in glowing lure to trap dinner. Some males even become permanent parasitic buddies to the females - imagine being attached to your date forever! Wild.

Floating around half a mile deep is the pigbutt worm - a tiny, glowing critter that looks like a mix between a teardrop and a balloon. It traps food in a mucous web and glows to scare off predators. Definitely not your average worm!

With teeth so big they look like shark fins, the Pacific viperfish is a night-time hunter that can open its mouth wide enough to swallow prey whole. Don’t worry though, it’s mostly after small fish and shrimp.

This fish literally sees through its forehead! Its glowing green eyes point straight up, scanning for food, but it can swivel them forward when it's time to eat. Talk about having eyes in the back of your head!

Don’t judge this jelly by its graceful moves - it’s a fierce hunter that swims with its tentacles out front, snagging jellies, comb jellies, and more. Tiny stinging cells act like Velcro to trap dinner.

The silky jelly is a quick-change artist and escape artist in one. It flashes blue lights to startle predators, jets away super fast, and drops sticky tentacles to confuse any would-be attackers. Slick!

These see-through squids are the ultimate masters of disguise. They’re so transparent they almost vanish but light up to hide their shadows during the day. When trouble's near, they ink, darken, and make a fast, spooky exit.

Not a plant but a living coral forest, bamboo coral grows ancient, knobby branches covered in tiny animals that catch food. It even fends off predators with stinging tentacles and glowing alarms, but humans are their biggest threat now.

This little worm has the ultimate defense: it shoots glowing green bombs! When threatened, it lights up and drops a glowing blob to confuse predators while it paddles away to safety.

Imagine a see-through shrimp the size of your hand with giant eyes and invisible armor. That’s the crystal amphipod, a master of deep-sea hide-and-seek and a jelly-aholic who munches on comb jellies using sharp little pincers.

With a serious scowl and teeth big enough to scare you, the fangtooth actually just waits for dinner to come to them. They might not see great, but they’re super sensitive to movement - and seriously hard to spot.

Breaking the squid rules with just eight arms (no long tentacles here), this squid flashes glowing tips and can drop an arm like a lizard’s tail. During the day, it hides deep; at night, it comes out to play near the surface.

This worm swims in open water, never touches the bottom, and can roll into a jelly-like barrel or squirt glowing fluid when scared. It’s also a fitness star, moving with graceful swishes and rowing motions that inspire underwater robots.

A bobbing blob in the ocean, the balloon worm looks like a jelly or an egg case, but it’s a worm! It floats around catching food in a mucous net and plays a big role in moving carbon around the ocean.

When it’s time to be a mom, this deep-sea squid carries its eggs everywhere in her arms - a rare squid parenting style. Researchers caught a glimpse of this brooding behavior and are still amazed by the dedication.

At a full meter across, this massive crimson jelly was a giant surprise when first spotted. No tentacles, just big finger-like arms, and it’s been spotted from Baja to Japan - proof the deep sea still hides plenty of secrets!

Dark-skinned and sneaky, dragonfishes wait patiently with glowing lures dangling to nab dinner. Popular deep-sea species like the Pacific blackdragon and longfin dragonfish are rarely seen but always impressive.

These massive worms live where hot mineral water bursts from the seafloor and don’t eat like normal animals - they team up with bacteria to make food right inside their guts. They’re fierce when protecting their feathery gills and adapt quickly when vents switch off.

This little octopus floats far from any seafloor hiding spots, using clear skin that can flash orange in a blink to vanish from predators. Moms carry eggs in their arms and dive deep for safer brooding, sacrificing themselves so babies can swim free.

Warm hydrothermal springs turn into octopus nurseries filled with purple mama octopuses guarding eggs for nearly two years. When eggs hatch, the moms die, but the garden buzzes with life as scavengers and tiny critters move in.

Big, bright eyes and sensitive chin whiskers help the rattail sniff and feel out dinner in the dark deep. As humans fish deeper and deeper, these slow-growing fish need our help to keep their populations safe.

Sticky fins help snailfish hold on tight in habitats from tide pools to the deepest trenches. Some snailfish curl up into a doughnut shape and float in midwater. A record-holder even lives 5 miles deep - talk about deep! MBARI helped name some new species too.

Equipped with arm hooks like tiny claws, these squids are fierce hunters (sometimes even eating their own kind). Mommies carry eggs in their arms deep and dark, fasting months just to raise their babies.

Painted pretty pink but deadly, this comb jelly hunts others and swallows them whole. Its crimson gut hides glowing meals so it stays undercover while prowling the dark depths.