In one of the last episodes of Conan that aired June 22, Conan O’Brien welcomed guest Seth Rogen on his show, and it led to a few surprises in a hazy showdown. At the request of Rogen, O’Brien did the unthinkable—taking a hit of cannabis from a joint while his episode aired on TV. O’Brien’s last episode will air today, June 24. According to the Wall Street Journal, O’Brien’s late-night run is coming to an end, after 28 years and 4,368 episodes spanning decades.

O’Brien has been loosening up and taking risks on his show, as there are fewer shareholders to appease. Because O’Brien is wrapping up the last episodes of Conan, and will soon have extra free time to pass along, he asked Rogen for some tips on how to pass the time away. Rogen whipped out a joint, which he of course was carrying in his pocket, and handed it to O’Brien. Rogen rarely strays very far without carrying a joint for emergencies—and it came handy during his appearance on the late-night appearance.

Conan O’Brien Segment

That’s when the episode started getting interesting, and an unplanned charade unfolded before viewers’ eyes. “I think you should take one hit of that weed,” Rogen said without hesitation. “And I think you’ll have a really good time.” O’Brien then responded, “Do you have a light?”

Rogen handed over the joint, and a lighter, but then O’Brien didn’t know which end of the joint to light, and admitted that his experience with cannabis is extremely limited. Then he toked up—a bit awkwardly, but with determination.

“When does this thing that’s going to happen, happen?” O’Brien asked, and then joked: “I’m driving a school bus in an hour.” Some commenters pointed out how the talk show host was suddenly becoming self-aware, when he can usually breeze through an episode. O’Brien attempted to move into the next segment of the interview, but Rogen was just too excited to hold it in. “I’m so happy with what just happened,” Rogen said.

O’Brien’s trusty sidekick and co-host Andy Richter also joined the circle as the episode aired. The night did not go the way viewers had expected.

Here’s the kicker: According to Rogen, the stunt was genuinely unplanned, and said on Twitter that he was terrified of getting O’Brien too high. Rogen called the event “surreal.”

Something about the whole scenario sounds familiar, and we’ve all seen this episode before. This debacle follows the notorious episode of The Joe Rogan Experience in which Rogan convinced Elon Musk to smoke a blunt, and nobody expected the contender for the world’s richest man to smoke a blunt on camera. Sometimes talk shows go off the rails into unplanned territory—and we’re grateful.

Catch O’Brien’s tearful last episode tonight—it may be your last chance to see “Coco” doing what he loves most. O’Brien plans on going out with a bang, as well. His last guest is scheduled to be Jack Black who will appear tonight. There could be more, as well, as the host mentioned “special surprise guests” in his final shows.