Evolution is responsible for creating some truly spectacular animals with no shortage of useful yet odd-looking attributes. The neck of a giraffe, the trunk of an elephant, the snout of a star-nosed mole — all creature features that we've become more or less accustomed to (well, maybe not the snout of a star-nosed mole). But when attention is turned to the denizens of the sea, things get even weirder. 

With only 230,000 species known and up to an estimated 10 million species of marine animals yet to be discovered, there's really no telling what's going on in the depths of the drink. What we do know, however, is that to us terrestrial observers, it's a place filled with undeniably unusual inhabitants. Creatures that are as odd and eccentric as they are beautiful — and all of which make cinematic aliens seem downright run-of-the-mill. 

For example, consider the hammerhead shark above. To most of us, these crazy-headed sharks are familiar enough that they barely cause a second glance. But when you stop and take a good gander, you think: dang that's a weird fish! (You can read about hammerhead sharks' cephalic exuberance in Why hammerhead sharks have such funny heads.) But the clunky-headed hunter doesn't hold a candle to some of the odder otherworldly occupants of the ocean. Here are just few of the known ones, and with millions left to discover, there's no telling just what other freaky splendors lurk below.

1. Leafy sea dragon

Leafy sea dragon

Kjersti Joergensen/Shutterstock

As if seahorses weren't weird enough, another member of the family, the spectacular "leafy seadragon" or Glauert's seadragon (Phycodurus eques), takes the family funny gene a step further with its extravagant array of seaweed camouflage. 

2. Lumpsuckers


k.steudel/Flickr and NOAA/Wikimedia commons

Hi, cuties! Looking like some kind of pocket aliens with attachment issues, the lumpfish's modified pelvic fins  have evolved into sticky disks which they use to hang on to things. And just to add to the really-odd-but-charming factor, many species have bony, wart-like tubercles protruding from the head and body.

3. Dumbo octopus

Dumbo octopus

Mike Vecchione, NOAA

For every cute or beautiful creature, there are many that look like this, Grimpoteuthis, also known as the Dumbo octopus. This creepy creature lives at depths reaching 23,000 feet below sea level, deeper than any other known octopus. It can make the transparent layer of its skin blush at will and has been measured up to six feet in length.
4. Longhorn cowfish
Longhorn cowfish

Drow male/Wikimedia Commons

Ok, quick, back to cute. The longhorn cowfish, Lactoria cornuta, is a type of boxfish that can grow up to 20 inches long. Known for their perky horns ... but what about those whistling kissy lips? As it turns out, they put their mouths to good use by blowing jets of water into the sandy substrate to root out food. 

5. Ornate ghost pipefish

Ornate ghost pipefish

Russell swain/Shutterstock

The ornate ghost pipefish (Solenostomus paradoxus) is both ornate and a bit of an apparition, just as the name implies. It's one of the hardest fish to find in the ocean, the Where's Waldo of the reefs, due to its petite size (12 centimeters long) and an appearance indistinguishable from the coral habitat in which it lives.

6. Mantis shrimp

Mantis shrimp

Image Focus/Shutterstock

Step away from the mantis shrimp; these utterly gorgeous crustaceans are nothing short of vicious vixens. They possess powerful claws that they employ in spearing, stunning and dismemberment. And if you think one might be safe in an aquarium, think again. Some larger species of mantis shrimp are known to have broken through aquarium glass with a single strike of the lethal claw.

7.Striated frogfish

Striated frogfish

John A. Anderson/Shutterstock

Who mixed up the fish with the fright wig? These hairy guys are weird to look at and have an even weirder method of procuring dinner. When their prey approach, they wiggle their "lure" appendage to mimic a worm, when the prey comes in to snap the worm, the frogfish rapidly opens its mouth up to 12 times its size, and the inward rush of water and prey are consumed in the blink of an eye. Imagine this fish with its mouth opened 12 times as large. Gulp!

8. Frogfish


Mark Doherty/Shutterstock

While it's true that this frogfish, from the same family as the hairy-wormy dude above, doesn't have the same wild texture, it's no less bizarre. While evolving some mind-boggling camouflage effects, it's also earned the prize for "fish most resembling an Easter Island statue." 

More on sharks and animal oddities from MNN:

Hammerhead sharks and 8 other fabulously freaky fish
Fleshy appendages, flamboyant camouflage, pouty lips and old-man faces swim rampant beneath the sea.