South Carolina’s Jadeveon Clowney could become the first defensive player to win the Heisman Trophy since Michigan’s Charles Woodson in 1997. (Al Messerschmidt/Getty Images)

When it was time to go, Jadeveon Clowney left Williams-Brice Stadium like he often does. He climbed onto a steel rail at the top of the stairs, smiled and slid — no hands, no worries.

“I do this every day,” South Carolina’s all-American defensive end said as he slid.

The best player in college football, and maybe the best college defensive player in at least a decade, doesn’t seem to think about falling or failing, about cause and effect, because so often he is the singular cause to so many astonishing effects. He decides on something; his 6-foot-6, 274-pound body makes it happen; and therefore it just is.

Defensive line teammate Kelcy Quarles said Clowney rolled out of bed one day and, without warming up, lifted 315 pounds to his shoulders. During the Gamecocks’ first practice of the season, Clowney and a teammate turned over a nearly 500-pound blocking sled. A few weeks earlier, he was clocked in an unofficial 40-yard dash at 4.46 seconds (For context, Robert Griffin III, the Washington Redskins quarterback who competed in the 2008 Olympic trials, ran the 40 in 4.41 seconds last year at the NFL combine). Clowney sleeps little, eats a lot and does the unthinkable.

“I don’t even get tired,” he said.

The Post Sports Live crew offers bold predictions for the college football season opener between Virginia Tech and defending national champion Alabama on Saturday. (Post Sports Live/The Washington Post)

These aren’t tall tales if they’re true, but Clowney is college football’s Paul Bunyan anyway.

“A freak,” Quarles said. “He just got hit by that thunderbolt from God.”

As a sophomore in 2012, Clowney had 13 sacks, and his explosive hit on Michigan running back Vincent Smith during the Outback Bowl was shown hundreds of times on highlight shows. Now entering his third season of college football — and almost certainly his last — he is seen as a Heisman Trophy hopeful, a possible No. 1 overall pick in next year’s NFL draft and the catalyst to sixth-ranked South Carolina’s best chance ever at the school’s first Southeastern Conference championship.

“Anything is possible with him, man,” South Carolina wide receiver Bruce Ellington said.

It’s not about the Heisman

Clowney’s sophomore season was so impressive that, for a while, it was believable he could sit out his junior season and wait a year to become eligible for the NFL draft. It might even have been smart. Last year, he watched as teammate Marcus Lattimore, a running back with similar NFL ability, suffered a season-ending knee injury for the second consecutive year.

Clowney, 20, makes no secret of his desires to play as soon as possible in the NFL, but he said he never considered leaving college early — at least this early. There’s too much left to do, and besides, the superhuman don’t consider long-term injury. They think of upside.

“It’s not about that Heisman to me,” Clowney said. “Heisman, that’s individual. But if we go out there and win all our games and the SEC championship and I get the number one pick, that’s the greatest feeling in the world.”

This is a program, mind you, that hasn’t won a conference title since 1969, when it topped the ACC. A team that went 1-21 combined in 1998 and ’99. And a team that had never won 11 games in a season until it did so each of the past two years, when Clowney and several other players who seem destined for the NFL signed to play for Coach Steve Spurrier in Columbia.

Clowney, though, was Spurrier’s greatest prize. Ranked as the nation’s No. 1 recruit out of South Pointe High School in Rock Hill, S.C., Clowney spurned a scholarship offer from Alabama’s Nick Saban, preferring to stay in his home state, where he had been mauling offensive players for a long time.

“I was aggressive at age 5, just trying to kill people,” he said, “They put it in my head early.”

He had eight sacks as a freshman and a year later set program records for sacks and tackles for a loss in a season. Clowney finished sixth in Heisman voting.

“I impress myself every day,” he said. “I get off the ball fast; I’ll be like, ‘I got off that ball so fast.’ Coach says he ain’t seen nothing like it.”

But it was his hit against Michigan’s Smith — Clowney flying past Wolverines left tackle Taylor Lewan and colliding with Smith, whose helmet flew backward and the ball came loose, before Clowney grabbed it with one hand — that made him famous.

It was aired repeatedly for months, and Clowney won an ESPY award for “Best Play.” It turned him into a folk hero capable of anything, moving the Gamecocks from prey to predators, led by a defensive end seemingly impossible to stop.

“I still get a kick out of it,” Clowney said of the video. “Everywhere I go, somebody pulls it up on their phone.”

NFL agents beckoned so often that Clowney told them to speak only with his mother. Still, Clowney drew controversy when he posted on Instagram a photograph of the rapper-turned-agent Jay-Z, after Clowney heard he was the next big fish for the Roc Nation agency, which has signed superstars such as Kevin Durant, Robinson Cano and Victor Cruz.

“I was just excited about hearing from him that he wanted me to be a part of that,” Clowney said. “I never talked to the guy at all.”

Autograph requests became so overbearing that Spurrier closed practices to the public. At the Gamecocks’ media day, Spurrier would barely discuss Clowney, saying he had received enough attention.

“We’ve talked about Jadeveon for seven months, after that hit,” Spurrier said. “He and Johnny Football [Texas A&M quarterback Johnny Manziel], those are the only two guys in America that we’ve talked about.”

In any good tall tale, Clowney has emerged as the giant, his future limitless and greatness almost certain, while others became victims — those Clowney stepped over on his way to the top. Asked if he feels any remorse for those poor souls, Smith and Lewan and others, Clowney smiled.

“Ah, no sir,” he said. “It doesn’t matter who it would’ve been.”

Facing the best

Jonathan Hurst had months to watch replays of “The Hit,” and he has no interest in being Clowney’s next casualty. Hurst is the starting left tackle at North Carolina, the Gamecocks’ first opponent, and he has heard many of the stories, seen much of the footage.

“Every single day,” he said. “I’ve probably seen it a hundred, two hundred times.”

Hurst is projected in many early mock drafts as a first-round NFL pick in 2014, but the reality of that will be determined in part by how he performs against Clowney. After the Outback Bowl, Lewan, a presumed high draft pick who seemed likely to leave school early, opted to return for his senior season.

Hurst knows that story, too, and is aware of the challenge ahead: Will Hurst handle the nation’s best defender, or will he be victimized by him, left to recover and ponder his future like the others?

“Good or bad for me, it’s going to definitely have implications,” Hurst said. “I need to have a good game, because if I don’t, it’s not going to look good for me and my future.”

So Hurst spent months training with Clowney in mind, telling himself that, no matter how hard his opponent was working, Hurst had to be quicker, stronger, more determined. He told himself that talent and hard work is better than talent alone, no matter how immense.

“I’ve got to do things that I’ve never done before,” Hurst said in June, long before lining up against Clowney.

A moment later, he went on.

“I want to know where I stand.”

Room for improvement

For his part, Clowney said in August that he hadn’t thought much about North Carolina, or about Hurst, or anyone else. He said he worked this season on improving only against his own expectations. Two years ago, he admitted, he didn’t give 100 percent of his effort.

“I was really running on speed and talent,” he said.

Even last season, he said, he wasn’t in ideal shape. He would get winded and head to the sideline, which is to say that, even in his remarkable first two seasons, there were weaknesses. He said he has spent these past few months working on those, honing his technique and pushing himself past exhaustion.

So he believes that, as good as he has been, he can be far better. And that his team stands to reach new heights, too. Still, Clowney said he doesn’t care much about becoming the second primarily defensive player ever to win the Heisman, but that — along with so much else — is possible. Clowney played a little running back in high school, but Spurrier has said he doesn’t plan to use him on offensive plays, which helped Michigan cornerback Charles Woodson win the Heisman in 1997.

But that doesn’t mean it won’t happen.

“If he wants to,” Clowney said, “I told him I can.”