Jimmy Fallon has some brutal theories about how Sen. JD Vance (R-Ohio) is preparing for the vice presidential debate against Minnesota Gov. Tim Walz (D).

“Right now, both guys are doing last minute prep. Walz is working on his comebacks, while Vance is thinking of a random group of people and a random pet that they’re eating. ‘Do we really need Swedish immigrants eating our guinea pigs?’” the comedian cracked on “The Tonight Show” Monday.

Former President Donald Trump’s running mate is set to face off against Walz, who is running alongside Vice President Kamala Harris, for 90 minutes on Tuesday night. The event will be hosted by CBS News.

“Today, Trump asked Vance if he needed any debate advice, and Vance is like, Absolutely. Do you have Kamala’s number?” Fallon joked.

He added that the Republican needs to learn how to do just one thing swiftly before he takes the stage.

“Vance is feeling good, and said he doesn’t have to prepare too much for the debate. All he has to do is super quickly learn what human interaction is,” he said. “Actually, Vance is very prepared. He’s already written a note on his hand that just says, ‘Don’t be weird.’”

Watch Fallon’s monologue below.