“If anyone falls asleep, I’ll f*cking teabag them.” Miguel Medina is sitting propped against the wall of a wide dirt pit dug into the ground maybe four feet deep. His eyes are closed, but he’s definitely awake, and he’s determined that his three teammates in the World’s Toughest Mudder stay that way, too. The four men of Wolf Pack Spartan Team are 25 hours into this 24-hour ultra obstacle race, and even though they’ve already won, they’re stuck out here, huddling against the 40-degree day, the fierce winds and the depths of their physical and mental exhaustion.

World’s Toughest Mudder is the hardest event on obstacle-racing giant Tough Mudder’s annual calendar. While most of the company’s contests are about 10 miles long with 20 to 25 obstacles scattered along the course, World’s Toughest packs 23 obstacles in half the distance, a punishing 5-mile loop that runners complete over and over again for 24 hours straight. The winners are the man, woman and team that finish the most miles in the allotted time.

Last year’s overall victor hit the 100-mile mark, but this new course is a doozy. Set against the backdrop of struggling master-planned community Lake Las Vegas, it features brutal desert climbs, taxing descents and watery inlets where mudders are forced to swim carrying a lit torch (an obstacle appropriately dubbed the Statue of Liberty) or hurl themselves off a 35-foot cliff (aka the Cliff). In between, they have to climb over walls, crawl under barbed wire, battle lots of mud and go through something wet and pink and gnarly dubbed the Birth Canal. Fail an obstacle and there are penalties—maybe a cinder block carry or extra walls, maybe a trip through the electric shock wires.

The race starts at 10 a.m. on November 15 under bright skies, organizers talking about sunscreen, heat stroke and hydrating, hydrating, hydrating. While the racers get acquainted with the course, pit crews set up tents in a base camp where competitors can stop to refuel, change clothes and rest during the race. But the winners rarely pause for long.

“It’s really the guys that can basically suck it up and mentally get through it,” says race director Nolan Kombol. “They aren’t the biggest guys and they aren’t the fastest guys, but they’re the guys who just have the most grit and fortitude, and they just put themselves through it. From what I can tell, they just say, ‘I’m not stopping. I won’t stop. I don’t need sleep.’

“There’s a type of person who thrives in an uncomfortable environment. ... those are the guys who are going to win.”

By 9 a.m. the next day—23 hours in—that guy has already won. 2013 champ Ryan Atkins has defended his title, amassing such a sizable lead over the nearest competitor that he’s able to call it a day an hour and a half early and still take the $10,000 prize. Total distance: 95 miles.

Women’s leader Amelia Boone is still out on the trail, finishing the lap that will bring her mileage count to 75—and she’s not alone. Bodies dot the course, most in wetsuits, trudging up the same hills they climbed all night. The temperature has plummeted and the windstorm that shook the Tough Mudder camp during the early morning is whipping up dust, turning an already challenging race into an ordeal and driving all but the hardiest competitors back to their tents. It looks positively miserable, but this is what WTM is all about.

Team-division winner Wolf Pack Spartan Team?

“They’re out there sitting on the course,” a Tough Mudder rep tells me.

The Tough Mudder rule book allows competitors until noon to finish a final lap as long as it’s started before the 24-hour cutoff at 10 a.m. That can be helpful, as in a competitor on the verge of completing 50 miles who just needs a little more time to bring it home. Or it can screw you hard. When WPST came in just before 10 a.m., they knew they were in the lead, but they also knew that Team Australia, with last year’s women’s winner, Deanna Blegg, wasn’t far behind. They could rest in camp, then race the Aussies for the $12,000 first-place prize, or they could keep going and protect their lead, staying on the course until the race finally ended at noon.

“We decided to be heroes and walk on,” says Hunter McIntyre. Only McIntyre looks rough. His face is sunburned, windburned or both, and he’s lying on a silver Mylar sheet a mile from the start line, attempting to stretch legs that have traveled 76 miles in the last day.

The whole team looks like refugees. Wrapped in space blankets and surrounded by discarded shoes, gloves and headlamps, McIntyre, Medina, Mark Jones and Dennis Welch are hiding out in this dirt pit, trying to stay warm and summon one last ounce of strength to see this thing through. The trials of the last 24 hours are written on every face and in every movement. Welch is completely covered in Mylar, so only one bare, tattooed shoulder shows. Medina’s wetsuit is pulled down to his waist, a blanket cinched around his shoulders and another covering his bare feet. He and Welch lean against the wall, heads on each other’s shoulders. It would be sweet and sort of peaceful if they weren’t so physically ravaged.

“I feel like I was in some sort of POW camp where they just tortured us for 24 hours,” says McIntyre. “I severely underestimated how tough it would be.”

“The only thing I’ve ever done that hurt worse than this was back surgery,” Medina adds. “Recovery lasted 6 months and I got a staph infection in my spine.”

Only Jones seems relatively unfazed, walking around the pit, pausing to stretch every now and then. He’s the one who’s been here before, who’s done a lot of ultra races, who got hypothermic during his first WTM and woke up naked in the medical tent with a granny saying, “We had to pull you from the race.”

“So this race meant a lot to me,” he says, and now the upstart underdogs, regulars in rival Spartan races, have won.

But it hasn’t been easy. First McIntyre was hypothermic, then Medina, the lead lost to Team Australia while the two men got warmed up and ready to run again. Welch had a penchant for wandering off, crossing timing strips that the whole team then had to touch within a single minute, and McIntyre turned hardass, strategizing that they would do three consecutive laps without pitting to make up for lost time. “I get a little cussy,” he says. “I don’t like losing.”

Jones found his nemesis was the Cliff, dreading the 35-foot plunge on every single pass. On their last full lap, he even tried to negotiate with his teammates to skip it and take the penalty, but they had a bargaining chip ... Jones trails off, leaving the obvious question hanging in the air.

“It shouldn’t be private information,” McIntyre pipes up. “Miguel pooped his pants.”

The circumstances are sketchy, but they involve a wetsuit, an impatient teammate, far away port-a-potties and the need to go—now. Standing in the center of the pit, Medina looks almost proud of his accomplishment. “That whole ‘anything to win,’ anything to win,” he says.

“I assume you’ve changed since then?” I ask.

Nope.

Is this what Kombol was talking about when he mentioned the mental fortitude and grit it takes to win World’s Toughest Mudder?

“Our goal from the start was to win it,” McIntyre says, his face now wrapped in his wet bib number to soothe the sting. “We’ve stuck it to everyone.”

The pit has started to seem like a weird little home, clothing, water bottles and empty energy chew wrappers scattered about. All four men of the Wolf Pack Spartan Team are huddled against the wall in a row, wrapped in foil like disheveled burritos. The wind is still pummeling them, the clock is still ticking and even as competitors stream by on the way to the parking lot, hot showers and a real meal, for these guys the race isn’t over. They’re tapped out, drained, totally demolished, but they’re also winners. Just 30 more minutes to go.