They start out small, experimenting with eating a bit of meat by munching on the tiny shrimp that also occupy the pond. Within days, they graduate with honors from Carnivore College and begin their transformation from Tadpole Jekyll to Froggy Hyde. They grow much faster than their algae-chomping counterparts, and their jaws get bigger and stronger. Their digestive tracts shorten in preparation for an all-meat diet, and their tails grow more powerful. Within a week, the normal tadpoles have mutated into 'roided up monsters.

Which is when the cannibalism begins.

David Pfennig
Lookin' good.

These killer tadpoles now see anything that moves as food, up to and very much including their own kin. And they couldn't stop even if they wanted to -- they are slaves to their hunger. It's like some sort of gypsy curse: forced to keep eating meat, any meat, family meat, or they'll quickly revert back to their smaller, weaker state and fall prey to the other monsters.

The weaker tadpoles are essentially powerless. They're almost a whole different animal. They're just down there, sucking algae at the bottom of the pond, thinking all is well, and then Jeff comes over to borrow a cup of sugar ...

National Wildlife Foundation
"Nice liver. Mind if I borrow it?"

Ah, we've all been there. You hit up a bar and find some hottie drunk enough to overlook your glaring personality flaws. You really start to hit it off, and then it turns out she's a giant demon that is eating your face oh God not the face you need that face to live!

No? In that case, congratulations! You are not a male cicada (we're sure you're very proud of your remarkable achievement).

Getty
Hooray.

In order to secure a mate, cicada males sing complicated seduction songs. If the female cicadas are, to put it technically, "down to clown," they respond with a specific set of clicking noises. It's a simple, fairly reliable deal. But just like every one of your drunken bar crawls carries the danger of waking up next to a fat dude named Loogie, the cicada mating ritual has its risks. Occasionally, the male cicada will hear a hot little female clicking and snapping all sexily and rush to the source, only to discover that he's been seduced by a massive predatory monster. Possibly named Loogie.

The monster in question is called the spotted predatory katydid, and yes, of course it hails from Australia. It employs a particularly dickish variation of aggressive mimicry, having developed a knack for recognizing the subtle nuances of a male cicada's boning song. It replies to these calls with spot-on imitations of the "Come get me, hunk" reply clicks of a female. Upon hearing what he perceives as a sultry siren's call to action, the male throws caution to the wind and rushes to meet his girl out in the old abandoned barn, only to find out -- surprise! -- it's a guy with a hockey mask and a machete. The katydid then grabs its unlucky suitor, bites a chunk out of his head to stop the struggling, and eats the rest of the body whole.

D. Marshall and K. Hill
The only 100 percent effective protection is abstinence, but who are we kidding?

Leave it to Australia to invent murder by cockblocking.

Picture a jolly termite going about his termite business -- crawling around, eating wood, shooting poison glue at enemies from his terrifying face-gun (oh, you didn't know they did that?). He may not be the biggest badass of the animal kingdom, but if your list of prey includes one guy with a face-gun and a bunch of dudes without face-guns, you'll probably opt to mess with the latter. So the termite's life is relatively stable.

Discott
"Live, love, shoot things with a face-gun. Just another day on the job."

One day, ol' Freddy Face-Gun notices a weird pile of gunk that seems strangely irresistible, yet somewhat ... off. Being a termite and thus lacking in the art of self-restraint, he shrugs, strolls over, and eats his fill of the delicious swill that should not be. Full and content, he heads home to tell his friends about the awesome, if somewhat disconcerting new food source he found!

Now, fast forward a bit. Freddy Face-Gun (who we hope nobody got too attached to -- we shouldn't have named him, should we?) is now a festering mass of horror and devastation, as what turned out to be his last meal is growing out of his body and devouring not only him, but his entire colony.

Paul Stamets via American Chemical Society
"Wasn't I just saying that Freddy would be the one to bring about the apocalypse? Mike, what'd I say?"

Said colony is just one of the many that have fallen victim to Metarhizium anisopliae, a peculiar fungus that kills insects in the most gruesome manner possible. In its dormant form, M. anisopliae is the Baconator of the insect world: It is unnatural, even unholy, and yet they still eat it -- presumably because it's 2 a.m. and they're drunk on little termite-beers.

A few hours, days, or even weeks pass without incident -- and then shit goes all Pinocchio and starts getting real. The spores that have been sitting dormant in the termite's body suddenly germinate. The fungus starts burrowing through the softer bits of the exoskeleton while eating the helpless insect from the inside out. Imagine you're a termite, just hanging around, all confident in your full suit of armor, staring people down with a gun that is also your face, when suddenly, the Double Down you ate a month ago starts spewing battery acid in your stomach and eating you right back.

Rob Graham and Jon Darbo, via Discover Magazine
"DAMN YOU, COLONEL!"

And of course it doesn't end with the death of just one termite. The delay effect in M. anisopliae means that the insect is back at its colony when the fungus starts to consume it. This was the fungus' intention all along. After consuming "patient zero," it uses the drained corpse as a base of operations and releases more spores into the vicinity, murdering everything that ventures near -- again, much like your bathroom the day after 10 PBRs and two Baconators -- until eventually, the entire colony is nothing but hollow, cracked exoskeletons.

By the way, science has recognized the destructive and repellent properties of the fungus and is looking into ways to employ it as a pesticide. So get a termite infestation, and this thing will soon be calmly sprayed into your house by surly dudes with prominent butt cracks. Don't be concerned: There's certainly no indication that M. anisopliae is harmful to humans. But then again ... isn't that exactly what the termites thought at first?

A study with the hilariously understated title "Bats Eavesdrop on the Sound of Copulating Flies" recently discovered that a European species called Natterer's bat spends an unhealthy amount of time listening to fly couples getting sweaty. And it's not just jerkin' it quietly in the other room while they get down, like your weird roommate who always wears a towel and nothing else.

Since the flies generally hang out on plants that camouflage them, the Natterer struggles to find them using its echolocation skills alone. The bat is crafty, though, and has taken other senses into the equation. Its good hearing enables it to locate the flies by their tiny fly moans and itty-bitty slap-and-bumping. It has learned to recognize the sounds of fly sex, is what we're saying here. Attacking the flies mid-coitus not only means that the prey is pretty preoccupied -- there's also the added bonus of catching two flies at a time.

Paolo Filipucci
Even if it does mean swallowing the occasional condom.

That's from the bat's point of view, anyway. The European fly's point of view is that they're forced to use the worst contraceptive in the history of humping: a huge, dark, toothsome monster that attacks them from the sky whenever they get down and dirty.

The horrid creature casting a shadow on our lovable bumbling bee-friends is called Apocephalus borealis, a parasitic fly with some terrifyingly xenomorph-like properties: It injects its young right into the thorax of a living bee, then lets the poor little guy go free. Well, "free" is such a relative term ...

You see, merely imitating one of the most terrifying monsters that human imagination could invent is not enough for A. borealis. While its fictional counterpart allows its victims a modicum of dignity, giving them full cognitive control before the inevitable dinner table chest-bursting scene, A. borealis instead turns the bee into a mindless living-dead slave for the remainder of its short life. Hence its lovely colloquial nickname: the zombie fly.

plosone.org
And they told us we were crazy to hoard shotguns.

While normal bees retire in their hives for the night, these zombees (that's seriously what they're called) leave their homes to confusedly roam the land, presumably emitting a low moan and waiting for the appropriately dramatic moment to attack passing insects for their brains. They continue wandering until they're irreversibly lost and exhausted. When they finally drop, so sick of un-life that they can't go on, A. borealis delivers the final blow and bursts out through the bee's abdomen, sometimes decapitating the victim in the process.

plosone.org
"Game over, man! Game over!"

Because every order of Genius Sandwich comes with a free side of Sick and Twisted Fries, the discovery of this hellbeast actually excited scientists, and they deliberately started forcing bees to hang out with the zombie flies. It was complete and utter carnage, to the point that A. borealis is now suspected to be a major contributor in the disappearing-bees epidemic of recent years. You know -- the one that some people see as a sign of the end times.

That's right: The zombie fly is such a terror, it technically qualifies as a horseman of the apocalypse.

For more horrendous scenarios from Mother Nature, check out 6 Animals That Kill Nature's Scariest Creatures For Fun and The 5 Stupidest Looking Superpowers in the Animal Kingdom.

If you're pressed for time and just looking for a quick fix, then check out The 7 Most Shameful Abuses of Bacon.