The shortened tusks aren't doing it any favors either. It's the one menacing weapon modern elephants have, and nature decided, "What if I try making them so short that they're completely useless and then use them as decoration on either side of a permanent guffaw?" The only reason these animals lived as long as they did was because predators could only laugh and move on in search of something less absurd to eat.

Paleontologists are still trying to figure out how this shark even fed itself with such an absurd mouth. The leading theory is that Helicoprion would have used its flexible jaw like a whip, lashing what was essentially a spiked tentacle into schools of fish and then pulling in whatever it managed to stab. But experts can't even agree on where Helicoprion would have stored its lower jaw when it wasn't using it to devastate swarms of prehistoric fish -- that's why different artists' renditions don't even look like the same animal:

Paleobiology.si.edu
"We're just pretty much guessing here."

Bruce Wendorff via National Geographic
"Oh yeah? Well, we can guess much stupider than you."

Originally they assumed that the teeth just rolled back under the jaw, but the most recent hypothesis is that the shark would keep them tucked neatly away in its throat, because obviously that's always the best place to keep a deadly coil of razors.

It's honestly surprising that anything else could survive with these wingless dragons sprinting around and eating everything. When the Earth hit the reset button with the Ice Age, we're fairly confident that one of the first changes on the list for new species was to give the crocodile at least one weakness.

Granted, Synthetoceras looks like it was invented by a child in a desperate attempt to make his love of unicorns more macho. But surely there must have been an evolutionary benefit to having a permanent antler on the front of the Synthetoceras' face. The going theory among experts is that they used them for sparring with one another, which is completely boring. We'll go on believing that they used their face horns as fancy little forks for feeding one another, thank you.

Evolution is lazy. It takes thousands of years to produce one minor change, and even then it will do the absolute bare minimum. Point in case, Odontochelys semitestacea. About 220 million years ago, turtles were essentially just drifting hunks of meat for predators. Finally, evolution stepped in and decided that it was only fair to give the turtles some kind of natural defense. The result? A hard belly, and that's it.

Odontochelys semitestacea was usually snapped up by whatever sea monsters lived in deep waters. Because the predators attacked from the bottom, the turtles that developed shells on their stomachs survived longer. The only problem was that as soon as anything figured out how to attack from the top or even bothered to flip one of these turtles around, suddenly it was the equivalent of putting a meal on a plate. If anything, the evolutionary advancement of Odontochelys semitestacea just made for fancier predators.

Guardian
"At least my horrible death was convenient."

Still, the fossil of Odontochelys semitestacea has helped paleontologists determine how turtles actually evolved their full shells. What they originally assumed was a thicker skin that evolved into a hard casing now looks more like extensions of the backbone and ribs that grew together over time to make a shell. But regardless of how important the discovery of this species might be, it still looks just like a naked turtle to us. One that's gone skinny dipping in some ancient pool, with its shell up on the shore.

We can't overstate how harmless and unprepared these walrus/whales were for the prehistoric world they lived in. To give you some context, they were around during the same era as the megalodon shark, an apex predator roughly the size of a blue whale, with five rows of teeth stretched across a 7-foot jaw. While it was technically carnivorous, Odobenocetops only ate clams and worms that it sucked up from the sand, and presumably it complained all the time about how nobody ever remembered to invite it to their birthday parties. That sad pout on its face almost makes it look like Odobenocetops knew just how ridiculous it was.

It seems unfair that while there are a handful of wildly different prehistoric versions of most species, the biggest variation among human ancestors was the slope of their foreheads. Sadly, evolution never experimented much with giving primates hooves or poisonous skin, so compared to nearly every other animal, our physical variances seem pretty lame.

Or at least they did until the 1930s, when a paleoanthropologist discovered the teeth of a primate that was over 10 feet tall and weighed around 1,200 pounds. For some context, a male silverback gorilla weighs about 400 pounds. Gigantopithecus was bigger than a polar bear and looked suspiciously like Bigfoot if he was making a considerable effort not to be shot during buck-hunting season.

Photos.com
And if you're friendly enough to him, he'll protect your rebel ass on Hoth.

The giant ape lived in the jungles of Southeast Asia, where it survived exclusively on plants and fruits, judging by the shape of its teeth. As horrifying as it might be to meet one of these monsters in the forest, there's a pretty good chance that our ancestors did occasionally. Gigantopithecus and early man were alive at the same time and lived in the same areas. In fact, humanity might be at least partially responsible for their extinction. Yeah, some things never change.

Agneeth has recently decided that he really needs to start being consistent with his guitar practice schedule, so you can see his progress here.

For more animals that don't look quite right, check out 15 Animals You Won't Believe Aren't Photoshopped and 8 Terrifying Skeletons of Adorable Animals.

If you're pressed for time and just looking for a quick fix, then check out 5 Bizarrely Specific Subgenres of Horror Movies.