Two glistening, sweat-drenched bodies are trapped in a cage, wrenching on the ground in anguish. There is tension and resistance, bursts of grunts, spasms and contractions. Repetition and compulsion. Pinning, hurling, squatting, writhing and heaving. Then finally, fatigue and collapse.

From a distance, the passion play unfolding looks like a flipbook animation of the Kama Sutra on steroids, or makeup sex between two people who forgot to make up. But this isn't an erotic game of Twister. It's mixed martial arts fighting. Combining elements of jiu-jitsu, wrestling and boxing, MMA has gone from being once viewed as bloody barbarism to one of the fastest-growing sports. And it has finally arrived in Nashville.

Tonight's match—the Gameness Fighting Championship at the fairgrounds—features 24 beefy fighters who will pummel, pound and pin for victory.

If you've never seen a real-life throwdown between two men, you're likely expecting a bloody, thwopping brawl of Fight Club proportions. The reality is simultaneously more thrilling and more benign. The initial charge at seeing hand-to-hand combat evokes something like shock, excitement, guilt and uneasiness. But then something strange happens: Your own bloodlust kicks in, and you can't turn away.

The entire cycle occurs in about five minutes. It begins when two shirtless, shoeless men enter the cage triumphantly and circle each other. It's like a brief flirtation on the dance floor, only with menace. They will swing, dodge and divert while standing, then quickly take it to the ground. Tonight's fighters—perhaps because they are so well matched in skill and experience—will spend most of their time on the floor grappling. For the uninitiated, the only way to describe this technique is something like resistance cuddling: Imagine being desperately compelled to physically merge every part of your body with someone you fundamentally loathe.

All around you, masculinity flows freely. Marines stand guard stiffly in one corner—they're sponsoring tonight's event, and they've attracted a crowd of ideal recruits: men aged 18-34 with high levels of testosterone coursing through them. White Zombie's growling muffler metal pumps overhead, and the aroma is a pungent combination of skating rink/high school basketball game: popcorn, seared meat, musky cologne and the undeniable scent of testosterone—potent, salty and addled.

A handful of girls traipsing around in skintight boy shorts and strategically ripped T-shirts agitate the mix. As a couple of these frosty-eyeshadowed lookers make the rounds, the men cock their heads to attention, scanning them with the kind of entitlement enjoyed only by a dude who's left the missus at home. They lean over the bleacher railing to get a better look at the unfortunately slim pickings. A few let out yelps like a prowling pack of boys cruising the strip on a Saturday night.

Fighter Thad Schlichter doesn't seem to notice. He's tonight's main attraction, but for now he waits in plain sight, quarantined off in one of two fighter's corners, his expression unreadable.

Twenty-four hours earlier, he was barely chattier. Waiting to weigh in at Ed Clay's MMA training facility off Nolensville Road, Schlichter, with his sleepy eyes, aggressively chiseled face and hulking frame, had the easy confidence of someone used to winning so often they become skilled in the art of humility.

"I've never been taken down," Schlichter said of his 7-0 record, politely averting his gaze. "But I'd be interested to see what it's like. You get out there to win, and you get all amped up. It's pretty intense."

He trains for a few hours every day and knows all he needs to about his opponent Josh Shockman, namely that he's an unbeaten Ultimate Fighting Championship veteran. But Schlichter isn't sweating it.

"I'm hoping for a better fight every time I go out there," Schlichter offered coolly. "And if you do take a loss, it just drives you to be better. But I haven't really experienced that yet." He adds an almost imperceptible shrug, as if the notion of losing is unfamiliar to him, even on a cellular level.

But that was last night. Tonight, he sits motionless, his stony gaze impenetrable as the crowd filters in. This is the third mixed martial arts card in Nashville since August, when the state legislature effectively dismantled a poorly run boxing commission that oversaw wrestling, boxing and kickboxing and added in regulations for Ultimate Fighting. So far, only amateur fights are legal, but it's only a matter of time before pros find their way to Nashville.

Eight of the fighters on tonight's bill are trained or recruited through Ed Clay, a former fighter who owns the largest MMA training facility in the Southeast.

Of the 12 bouts tonight, a few last mere seconds, while others go on for multiple rounds. The competitors look so similarly built that the only visible distinctions are race, shorts, tattoos or the presence of hair—meaning Mohawks. Their techniques are equally difficult to sort out, as are the reasons each fight is won.

A knockout punch is a no-brainer, but a chokehold or a nearly broken arm that spells the end is difficult to detect from the sidelines. There are a few rules—no biting, eye gouging, groin punching or fish hooking (jamming your fingers into an orifice and pulling)—but otherwise anything goes. And unlike the first Nashville fight that took place at Wildhorse Saloon a few weeks ago, these men are trained. They're still considered amateurs, but this isn't a show-up-and-you're-on-the-card affair.

The crowd is trained as well. They've been watching pro fights on TV for years, even traveling to Ohio and Kentucky to catch a match. They're everyday men in camouflage hats and work boots, in heavy leather coats, puffy white tennis shoes and hoodies. A large contingent sports Affliction, a clothing brand of T-shirts and hoodies featuring Celtic crosses, flaming skulls and intertwining pistols. They clutch 16-ounce beers, hooting every time a fighter has a clear advantage. "Get him!" or "Take him!" they scream. "Kick his ass!"

But for all their seasoned antics, this is still a brand-new drug for Nashville, and this crowd shows no signs of embracing mere casual addiction. More intriguing is that in their eyes, this surprisingly sensual match of brute strength between gleaming warriors appears to have all the potent, indisputable masculinity of chopping wood.

The fights wear on, match after match. This one collapses dumbly with a bloody nose, that one's arm looks painfully mangled. Two girls strut in the cage, sauntering around with placards indicating the round changes, a ritual cleansing.

Then Schlichter is up. The fight turns to grappling in a flash, but unlike most of the other matches, it seems to stay there longer. His opponent gives him a squat he can't refuse, and for several minutes they appear to only writhe. There are two men with frightening, near-equal strength who appear to be slowly exhausting each other. Schlichter wears shiny boxing shorts with "Jesus Didn't Tap" emblazoned on the back. Then Shockman delivers him a knockout punch.

Just like that, it is over.

Schlichter has lost his first fight. He looks surprised. He's quickly escorted away by handlers who shout the gathering crowd back. But this towering Adonis of a man, who just 24 hours earlier appeared coolly confident, still manages a quick smile as a reporter grabs his arm—both clammy and searingly hot to the touch, as if it's an electric force field emitting a jolt of heat—to ask how it feels to lose for the first time.

"It doesn't feel good," he mutters, averting his gaze again. "I'm gonna take off."

Schlichter's eye already bears a dark, purple bruise, and his lip is slashed, a thin line of blood forming under a sheen of sweat as he disappears into the shadows.