During his monologue, the late-night host showed a hilarious (and heavily edited) video in which Trebek was manipulated to appear as he if was laughing at Jeopardy contestants, interrupting them and reading clues about Bruce Willis butt-dialing someone's mother-in-law and Hugh Jackman's "saclike body cavity."
However, Trebek got the last laugh when he surprised O'Brien during his monologue. "I'm not upset," Trebek said. "I'm here for another reason. I'm worried about you. I've been watching some of your monologues lately and I'm concerned. I think you are starting to lose it."
Trebek then introduced an equally funny, and similarly manipulated video, to make O'Brien look "foolish" as well. Check out the video below:
Conan airs weeknights at 11/10c on TBS.