We live in an age where maps only have undiscovered areas, not warnings of “here, there be dragons.”

But every once in a while, Nature likes serving up some weirdness at the party, reminding us that even though we may have seen much of the figurative surface of the ocean, there’s still quite a few thousand cubic feet that we haven’t even shined a flashlight in.

Here are some weird fish – some already known and living where we can see them, and some which are little more than nightmarish mysteries of evolution.

Anglerfish

These fish are contenders for the ugliest fish species on the planet, what with their wide mouths and sharp teeth, connected to a body that seems too small.

But the killer detail is why it’s called the anglerfish: it has a spine that is used as a glowing lure to make fish come close. After that, it’s all about poor victims having a much-too-close look at the anglerfish’s teeth before they become dinner.

Blob Fish

This fish is disturbing because while it does look like a bit of a formless blob with a tail and fins, the face can sometimes look a bit too human – or, perhaps a minimalist cartoony version of a person’s face. It’s a certified scavenger, expending as little energy as possible, moving very slowly.

Leafy Sea Dragon

This sea dragon is one of the most successfully camouflaged fishes in the world, as with its coloration and body shape, it looks exactly like a piece of seaweed floating by.

Even better, it has near invisible fins, so the illusion won’t be broken so easily. It’s even been known to “float away” like a shred of plant life!

Goblin Shark

This deep-sea shark can grow up to 4 meters long. And although it’s a slow mover, it has a specially hinged jaw area that allows it to extend its bite action outward, as if the mouth and jaws were independent of the head itself, something that is sure to give us nightmares.

Longhorn Cowfish

Okay, cowfish are actually colorful, cute-looking cross between a mini-bus and a small fish, given its boxy shape and penchant for being very good at hovering.

It’s even considered a delicacy, but before you eat one, do recognize that it also has a very deadly poison all over its skin. It’s a cute little fish that packs a killer poison punch.

Viperfish

Viperfish are perfectly made for horror movies – long, narrow bodies that end in a mouth full of long sharp teeth – and in this case, curved backward. This assures it that once it bites, it won’t easily be detached.

Like the anglerfish, it has a little lure, but we’re sure that the teeth alone can more than make sure that anything smaller fish will be easy prey for this grotesque creature.

Stonefish

Stonefish are the poster boys for shallow-water weirdness, looking exactly as their name suggests, but with an array of spines along its back that make them the most poisonous fish in the world.

Aside from their weird looks, what makes them creepy is that you really won’t be able to tell if you’re about to step on one, thanks to the fact that they do look like rocks.