When you think of the Attitude Era's most iconic insults, "shut up juice" probably isn't the first one that comes to mind—but it should be. And believe it or not, we have late-night legend Conan O'Brien to thank for it.

In a recent episode of Conan O'Brien Needs A Friend, the comedian shared the hilarious origin story of how one of his silly catchphrases ended up in a WWE ring. During a conversation with guest Zach Galifianakis, Conan recalled his old habit of telling people, "Why don't you have a big tall glass of shut up juice?"—a childish put-down he admits was "really stupid" but couldn't stop using.

Enter Tommy Blacha, one of Conan's former writers who left to write for professional wrestling. Blacha gave Conan a heads-up before the bit aired, feeling like he might have "stolen" it. But instead of being upset, Conan was thrilled. He tuned in to Monday Night Raw and watched as The Rock—the most electrifying man in sports entertainment—delivered the line to perfection: "Hey, I'll tell you something, maybe you should just go have a long glass, tall glass of shut up juice."

The crowd went wild. Fans in the arena were shown holding their heads in disbelief, as if to say, "The Rock got him!" But the fun didn't stop there. The following week, a fan showed up with a sign reading "shut up juice," and Conan says he was "in heaven."

It's a small but brilliant example of how even the most random pop culture moments can find their way into WWE history. Blacha later confirmed in an interview with Tales From The Attitude Era that Conan was genuinely flattered—and the story has become a favorite whenever wrestling or Blacha comes up in conversation.

Now, if only we could get a clip of Conan delivering the line in full Rock mode. That would truly make our day—and probably sell a few "shut up juice" t-shirts while we're at it.