The Piranha is a member of a family of omnivorous freshwater fish which live in South American rivers. Yet another reason why I'll never go to South America along with malaria and those little fish that go up your urethra.
If we were to go by looks, this is pretty much a fish Satan would've kept in his aquarium if the water didn't evaporate every 7 minutes. Aside from those hippie piranhas I mentioned earlier, piranhas are part predator, part scavenger. So they'll eat anything that seems vulnerable, like an injured fish or your wife who thought it'd be nice to swim in the fucking Amazon River.
Of course, they'd never attack a healthy living thing like your wife...unless they smell her blood. They only need the scent of blood to go apeshit bonkers and try and get some of that fresh wound. When a school of piranha are feeding, the water appears like it's boiling and it'll churn red with blood. They attack with so much vigor that they can strip an animal of its delicous flesh in a matter of minutes. While it's still alive. Just like in your nightmares.
Imagine 20 of these all at once.
They'll even eat that tasty bait you've been using to go fish with. Don't get too busy shaking your fist in anger though, or you might miss the piranha's brethen trying to bite at it. That's right, they're also cannibalistic. If they don't get enough to eat, they'll just go and eat the weaker fish in their group. They'll even eat their own babies.
"Hey guys what's up?"
"Jed, how long has it been since we've eaten?"
"6 days, why?"
"Oh you'll know soon."
But other than that, they mostly only scavenge for animals that are either already dead, injured, or weaker than themselves. Despite being called a fearless fish, they're actually very docile, going in groups to deter other predators from feasting on their organs. Hell, it's usually the red-bellied piranha being identified as the aggressive horror beast everyone talks about, and even then they aren't as dangerous as depicted. For the rest of them, they're more pests then anything else really, as they usually steal fishing bait, ruin caught fish, and eat through nets with their damn teeth. Yeah, screw you pirahna and your small schools of scavengers. At least it's a good thing they can't fly right?
Oh fuck off Hollywood.
The Media and Legends. Or Medgends, whatever floats your boat.
The legends of them eating a man to the skeleton started with President Theodore "Motherfucking" Roosevelt's safari adventure to Brazil during his travels. Brazilian fishermen wanted to give the man good ol' entertainment to impress him. And by "fishermen" I mean "assholes." And by "entertainment" I mean "blocking off part of the Amazon River with rope and dumping hundreds of hungry fucking piranhas into it before Teddy came upon it on his hunting trip." They then dumped a cow into the river to be devoured by the starving piranha within minutes down to the bone. Right in front of the goddamn President himself, thus giving more evidence that fishermen back then were massive dicks.
Nevertheless, Roosevelt was very impressed and somewhat unnerved, and wrote in his book Through the Brazilian Wilderness that piranhas were vicious creatures. That's right, even President Badass himself admitted that these fish were quite intimidating.
"Well at least that ferocious lion wasn't as vicious as those goddamn piranhas."
Ever since, the public ate that shit up and just took it from there. There were films like the B-movies Piranha and Piranhas, which featured coldwater man eating piranhas made by the government that get accidentally released into the local river and even in that James Bond movie You Only Live Twice, where a henchmen named Hans is shown feeding live humans to pet piranha owned by the villian Blofeld. Do they still eat humans anymore, we need someone to look this shit up?
Even if these movies are really cheesy, it's done nothing to quell piranha fever, and with the upcoming release of Pirahna 3D, who know where they'll show up next.
Though "I'm tired of these muthafuckin' piranhas on this muthafuckin' escalator!" isn't that catchy.