If you thought daredevil Johnny Knoxville was out of his freakin' mind on MTV's Jackass, just wait until Jackass: The Movie arrives in theaters later this summer. "It's the show times 10," he tells TV Guide Online with a grin. "We got an R rating and we took full advantage of it."

Knoxville — facing heat after several teens injured themselves while trying to mimic his Jackass pranks — abruptly ended the MTV series last year. "Washington came down on MTV and then it trickled down to us," he recalls. "Near the end, there were only, like, six people working in the office. I was like, 'This is not what I intended.' I wanted to quit the show while it was still funny."

As a result of Jackass's sudden death, Knoxville was left with a backlog of stunts — many of which were incorporated into the big-screen version (opening Aug. 9). "There were things we shot that we couldn't put on television," he explains. "There was so much footage lying around, and we just made the best — or the worst — 90 minute [movie]."

Not surprisingly, Knoxville was hesitant to give away too many of the film's sordid secrets. But he did offer this warning: "You'll never look at little toy cars the same way again in your whole life — I guarantee it."

The 31-year-old Tennessee native — who plays a two-headed alien in Men in Black II (opening July 3) — also reveals that Jackass: The Movie will feature several celebrity cameos, including one by character actor Rip Torn (The Larry Sanders Show). And what about a sequel? Winks the porta-potty prankster: "I don't know what else we can do, honestly."