Although a lot of late night show hosts are on vacation/in reruns this week (namely Jon Stewart, Stephen Colbert, David Letterman, and Jimmy Kimmel), Jimmy Fallon, Conan O'Brien and Seth Meyers are all on air this week—and they all paid emotional tribute last night to Robin Williams a day after he was found dead at 63.

"You'd watch him and you would cry laughing," Jimmy Fallon said. "And you would think, 'I'm never going to see anyone like this human, ever.' It's just amazing. His brain was always thinking 10 steps ahead of what he was saying. He was like the Muhammad Ali of comedy." After showing a clip of Williams's first-ever Tonight Show appearance with Johnny Carson, Fallon ended his segment by standing on his desk (Dead Poet's Society style) and saying, "O Captain, My Captain—you will be missed."

Conan O'Brien, who was taping his show when he learned the news of his death on Monday evening, told an anecdote about Williams buying him a bike when he was "feeling low" a few years ago due (likely during The Tonight Show brouhaha).

"Out of the blue, Robin Williams buys me a bicycle," O'Brien said. "It was the most absurd bright orange and bright green bicycle with shamrocks on it. So I called him up and all he could say was, 'Does it look ridiculous? Will you look stupid riding it?' He had just that amazing spirit of fun."

And Seth Meyers also paid tribute, putting an emphasis on the need for more discussions about mental health issues: "The saddest part of this is Robin was battling depression. And if there's anything we can do to honor his memory, I would hope it would be to use this opportunity to educate us more about this terrible affliction," Meyers said.