Cage the Elephant’s Jared Champion’s appendix burst Monday night. Luckily, Dave Grohl was nearby, available to help. The always awesome Foo Fighters leader didn’t actually perform any medical procedures on the Kentucky rocker, but he offered to fill in for the drummer at the band’s show in Salt Lake City, Utah, at the Maverick Center (Cage are currently the opening act on the Foos’ tour supporting Wasting Light). “He had an ulcer for a couple days, then at 1 A.M. it was just unbearable, so he went to the emergency room,” guitarist Lincoln Parish tells SPIN. “He was rushed straight into surgery.”

Enter Grohl. “Dave somehow heard what had happened and called our tour manager. He said, ‘Hey, so do you think the guys would go for it?’ ” Parish says. “Our manager was like… ‘Um, yeah!!!‘”

While he currently fronts the Foo Fighters, Grohl has never strayed far from the seat where he once made history, as you may recall, and he agreed to join Cage the Elephant on the songs he’s most familiar with, including “In One Ear,” “Shake Me Down,” “Sell Yourself,” and “Ain’t No Rest for the Wicked.” Cage the Elephant kicked off their set with another fill-in drummer (the tour’s monitor engineer), and then Grohl came on for the set’s last five songs. The crowd, understandably, howled when he stormed the stage.

“I had to pinch myself,” says Parish. “I turned around and Dave Grohl is playing the drums. It’s an amazing, once-in-a-lifetime experience. Nobody can replace Jared. But…it’s Dave fucking Grohl. If you’re going to be replaced by anybody, it might as well be the best.”

Actually, it’s a twice-in-a-lifetime experience: Grohl has agreed to again join the Cage boys for a portion of their set at the Forum in Los Angeles on October 13. It’s a move indicative of the two bands’ friendship, says Parish. “I’ve never met a group of more humble musicians,” he explains. “We sat down and had dinner with Dave last night. He’s like a friend you’ve had for 20 years. It’s like you’re talking to your old buddy from high school. The first night of the tour, as soon as we got offstage, Dave had shots of whiskey. Last night he came into the dressing room with moonshine.”

The two bands met at KROQ’s Weenie Roast in L.A. last June. “Jared ran into him backstage before the show and said, ‘Come check us out!’ He did. Dave saw the last two songs of our set, and afterwards told [frontman] Matt [Shultz] that we should do some shows together. Two weeks later we got the call offering the opening spot on their tour!”

But what about Jared and that appendix? “He’s getting released from the hospital today,” says Parish. “He’ll stay in Salt Lake tonight and then fly into L.A. tomorrow, when he’ll jump back on the bus with us. He’ll probably be back onstage by San Diego [on October 17]. He’s a trooper.”

In related news, Cage the Elephant released a new music video for “Aberdeen,” the third single off their sophomore album Thank You, Happy Birthday. “It’s a Claymation video about this dragon monster that goes through all these scenarios in which the best outcome isn’t attainable,” says Parish. “We’ve wanted to do a Claymation video for a long time. It’s something different that people will dig. We were going for an old Gumby feel, since we all watched it growing up [laughs].” Aberdeen…Dave Grohl. Okay, we get it, guys.