The Predator
The Predator is a goddamned professional top-rate intergalactic asskicker who flies around the galaxy in an invisible spaceship killing tough-ass alien warriors and turning their skulls into beer mugs just for shits and giggles. That alone should make them worthy of a spot on this list, but there's much more to the Predator than just spending the last several centuries playing out a really high-tech remake of The Most Dangerous Game and leaving a trail of dismembered mutilated alien carcasses littered throughout the galaxy.
For starters, the Predators are fucking tough as shit. You can shoot them in the chest, hack off their arms and crunch them in the scrotum with a tack hammer but they'll still find a way to tear out your spinal column Sub Zero-style with their one good hand and then use your severed head to violently bludgeon all of your squad mates to death while shouting the word "motherfucker" at your grandmother. They're stronger than like three roided-out Arnold Schwarzeneggers put together, they can take like 100hp of damage without even blinking, and they can jump like fucking Carl Lewis on a trampoline on the surface of the moon. They're also the ultimate duality of badassitude because they've got awesome dreads and cool-as-shit green blood, but they're also really really fucking ugly. It takes a true badass to simultaneously look awesome and disgusting.
As if it's not enough that they could beat a pickup truck in an armwrestling competition, they've also got all sorts of badass technologies that help make them the ultimate killing machines and the most hardcore motherfuckers in the universe. They've got a totally sweet active camouflage that makes them pretty much invisible to the human eye, their helmets allow them to see every spectrum of light ranging from infrared to ultraviolet, and their body armor is pretty much impervious to everything this side of that whack-ass acid blood the Aliens secrete every time a Predator jams a pair of rusty scissors into their eyes.
Probably the most badass thing about the Predator is his massive arsenal. He's got more melee weapons than an entire longboat of viking warriors, packing everything from wrist-mounted retractable twin blades that make Wolverine's claws look like dulled plastic kiddie butter knives to a seven foot long telescoping harpoon the likes of which could kill every whale in existence at the same time (assuming you threw it at the right angle). In the rare situation that he doesn't get close enough to shiv you like a maladjusted prison inmate who forgot to take his anti-psychotics, he can also fire motherfucking buzzsaws out of his suit that are capable of slicing through an entire SWAT team in one shot or blow your goddamned head off with a shoulder-mounted laser cannon. If for some reason none of this manages to kill your stupid face, he's also got a fucking nuclear warhead strapped to his arm capable of turning everything within twenty square miles into a giant pile of charred ass.
Another awesome aspect of the Predator is his honor code, which has been the mark of hardcore badass warriors throughout history. For example, Predators won't kill unarmed non-combatants, which is pretty damned admirable. Sure, they're only refraining from pulling your eyes out because you're such a pathetic target that there's no honor to be gained by your complete and total destruction, but hey, at least you're not getting skinned alive and hung upside down from a tree in the middle of the jungle somewhere or having your legs blown off at the knee by a plasma caster. For Predators, it's all about the honor, and the honor comes from killing worthy opponents. That's badassery right there. If they can't get the job done, they also understand the benefits of taking everyone else in the universe down in flames with them. Since nobody gets the better of a Predator warrior and lives to tell the tale, if he's about to die from his wounds he activates the self-destruct on his wrist and leaves behind a gigantic fucking smoking crater in his wake, obliterating himself and any bastard lucky enough to get a cheap shot in on him.