Conan O'BrienYou see the Conan O’Brien show this past Friday? He straight busted his head.

“As many of you may know, on this past Friday’s show I was doing a stunt and I hit my head and suffered a slight concussion. And I promise, if you’re a good audience, I’ll do it again tonight,” O’Brien said during Monday’s taping.

In a transcript released by NBC, he joked that he struck his head so hard “that for five seconds I actually understood the plot of ‘Lost.'”

O’Brien and guest Teri Hatcher were in a footrace when he tumbled, forcing Friday’s show to be halted. He was taken to a hospital for examination, and a “Tonight” rerun aired instead of the planned episode.