Watch Danny DeVito, Jimmy Fallon Play Inflatable Flip Cup

Actor also recalls insult ice-breaker during Taxi' audition, hilarious nude scene in 'It's Always Sunny in Philadelphia'

"You've gone from Taxi to this," Jimmy Fallon cracked at Danny DeVito during Tuesday's Tonight Show, as the duo geared up for a game of inflatable flip cup. "When this is over, I'm gonna kick your ass," the actor fired back. Host and guest channeled their inner frat boys as they raced to down Solo cups of beer and flip over the cups, all while wearing random poofy suits. 

Fallon took an early lead in the contest, holding on for a victory – despite a strong surge from DeVito, whom Fallon calls "the coolest in the school."

Elsewhere in his visit, DeVito talked about his unorthodox audition for the role of iconic grouch Louie on Taxi. "I really wanted to capture Louie," he said. "These were very famous people who wrote the show. Jim Brooks, Ed Weinberger – they created Mary Tyler Moore; they were the hot shots. The casting director said, 'This is a great part for you.' So I really got into it. I wanted to figure out a way to really make an impression.

"So I come into the room," he continues. "They're all sitting around in this really well-appointed office. They're all sitting there, the producers and whatever. I just walked in. You see the seat where you're gonna do your audition. That's the hot seat. I got the script in my hand. I walk in, took one step and said, 'One thing I wanna know before we start: Who wrote this shit?' I took one step in total terror, and then they just laughed. The rest of the time, it didn't matter what I said. I could say 'And,' and I got a laugh. That's Louie."

In a web exclusive, DeVito also detailed his "weirdest experience" as an actor – a hilarious nude scene on It's Always Sunny in Philadelphia

"I read the script; it was really cool," he said. "It was like The Ghost of Christmas Past, where they wanted to show Frank Reynolds' character, what kind of an asshole he was. They take him to a dinner party or something, and I get sewn into a leather couch. I get hot in the leather couch, sweating, and when I come out, I've taken off all my clothes. So it's like a nude scene.

"But you forget you're in a scene where there's like 50 background actors there," he continues. "You come out of the dressing room naked, and they grease you down because you've gotta be sweaty. Which is good, the greasing down part. But then you gotta pry your way out of a coach like a flounder, a halibut, totally greased up, naked, and you forget there's all of these people there — that I didn't know. It's weird. But I did it. I came out. And my first line is, 'Hot, hot, it's hot.' I'm sweating. But I'm naked." 

Castmate Kaitlin Olson had the next line, but she was so shocked by the site of a greasy, naked DeVito that she spaced out with her mouth gaping.

"That's not the first naked scene I did, though," he adds. "I did one in a Tim Burton movie called Big Fish. But it was different. It was darker. It was at night."