Michael Keaton and Paul Schaffer were on hand to help the late-night host reminisce about the unaired bits from the show

It’s officially the last week of The Late Show. For one of his final episodes, Stephen Colbert paid tribute to some of the worst ideas the late-night show has had, including dressing Michael Keaton up as a pigeon.

Monday night’s show opened with a bit featuring Keaton, who appeared outside Colbert’s office window as a literal bird man. In the clip, Colbert was struggling to come up with a show idea featuring the actor when he spotted pigeon Keaton tapping on the glass and strutting outside. “That pigeon looks just like Michael Keaton,” he mused. It turned out to be a surreal dream, in which Keaton and Colbert, both as pigeons, fought over a slice of old pizza.

The real Keaton eventually woke Colbert up and the duo discussed Colbert’s idea to have a celebrity dress up like a pigeon as a bit. After Keaton told him he loved the idea, Colbert admitted, “Here’s the thing: We ran out of shows and we couldn’t fit the bit in. But then I thought, ‘Wait, what if we did a worst of The Late Show episode?’ It’d feature all of the weird bits that either completely failed or things that we as a staff liked but thought the audience would absolutely hate.”

He added, “You know, as if the ratings didn’t even matter any more.”

That become the theme of the entire episode, which celebrated several very dumb ideas from Colbert and his writers. “There’s so many important things going on in the world, but a lot of that stuff’s a drag,” Colbert told the audience before skipping his monologue entirely. “Here’s the deal: We thought we might just take it a little easy tonight because we’ve been doing this show for almost 11 year, almost 1,800 shows at this point.”

He noted that they definitely had enough material for a “best of” clip show, but instead decided to focus on the worst idea. “We thought it would be more fun to show you stuff we’ve made and never aired and call it ‘The Worst of The Late Show.’ Although technically what you’re about to see is the best worst stuff we ever made. Still, not great.”

The episode included Colbert reminiscing on some odd and unfortunate moments from filming The Late Show, and the host chatting with some of his staff about their roles on the show. Towards the end, Colbert brought out staff writer Michael Cruz Kayne for a musical number called “It’s Raining Fish,” which got an assist from Paul Schaffer.

The Late Show will air its final episode on May 21. Tonight’s episode will feature interviews with Steven Spielberg and Colbert’s Daily Show cohort Jon Stewart, as well as a performance by David Byrne with Colbert. The Wednesday, May 20 episode will include a performance by Bruce Springsteen as well as appearances by special guests, with Colbert also answering his own “The Colbert Questionert” for the first time.

As previously reported, the other late-night shows will cede the spotlight to The Late Show on Colbert’s final night, with both Jimmy Fallon and Jimmy Kimmel airing repeats on May 21.