"Not at all. Life is cruel. I’ve seen the darker side."

I meet Ayrton, who is 9 years old but is the size of a six-year-old. Ayrton’s father, Keith—a racing fanatic who named his son after the late Formula 1 driver Ayrton Senna—explains to me that his son had a growth-hormone deficiency.

"He was getting picked on in school," he says. "Beforehand, I was like, MMA is trashy. It’s low-income. It’s rednecks beating each other up. But this has done a lot. The bullying is completely a non-issue now. Just because he’s little doesn’t mean he’s insignificant, you know?"

(Not all of the kids are here because of bullying. I also meet Haven and Jadyn Fielder, the sons of Texas Rangers slugger Prince Fielder, and they are just as sturdily built as you would expect the children of a Fielder to be. "Jadyn’s better at skating and fighting," says Haven. "I’m better at baseball." "You’re better at just laying on people until they suffocate," Jaden says.)

I also meet Dominic, an autistic boy who begins the class wedged into the corner, talking to himself. Dominic has been with 6 Levels Orlando for four years now, and he’s one of many autistic kids who come here. His mother, Lauri, watches from the seats nearby and explains how MMA has helped him come out of his shell a little bit. Dominic still has bad moments, though, so Lauri took a self-defense class here to defend herself against her own son: "I was getting punched in the face, kicked. When he gets mad or irritated, it’s like the Hulk comes out. He can overpower me in an instant."

Bullying is the number one reason kids wind up here, I quickly learn. Only a handful of the kids at 6 Levels have never been bullied, and all of their parents fear it. (One mom told me that a bigger kid once warned her son not to wear the color red "because it’s only for him.") If the parents not here to stop bullying, they want to stop it before it happens—to spare their children from the misery of being hounded every day until their self-worth is a speck of dust. You can sense their fear. You can see how much it would break their hearts to see it happen, to let it happen.

"How hard should I hit you?" I ask Ryan, who has locked us inside the 6 Levels octagon.

"As hard as you want to be hit back."

I make a mental note to not hit Ryan too hard.

"If you want anything to stop," he says. "Say ‘tap,’ or you tap me. Okay?"

"Okay."

In an instant, Ryan has my head locked under his armpit, with his forearm wedged against my throat. He gives a squeeze and now I’m experiencing entirely new shades of pain. It’s the kind of pain that eliminates the past and the future. There is only NOW OH GOD THIS IS HAPPENING TO MY NECK RIGHT NOW. I forget to tap Ryan to get him to stop. I try to say "TAP" but my voice has been stuffed back down into my diaphragm. Ryan senses my alarm and lets go. I slump to the mat in agony.

"My God," I wimper. "Oh, my God."

"You gotta tap! I didn’t know you were tapping! You okay? You okay?"

"I’m all right."

"Sorry, Drew. So, that was called a guillotine choke."

Ryan tells me there are two kinds of choke holds: blood chokes and wind chokes, so named for the precious resources they withhold from your brain. "Blood choke" sounds way worse (and also a fine name for a metal band), but it’s wind chokes like the guillotine that forcefully cut off your air supply (hence the name) and make you feel as if you are being internally decapitated.