After delivering a speech last week in which he labeled Donald Trump a “phony,” a “fraud,” and “very, very not smart,” Mitt Romney brought his #NeverTrump campaign to Jimmy Kimmel Live Tuesday night. And Jimmy Kimmel, who was tougher on Trump than some other late-night hosts have been, was a willing partner in the effort.

“This is the first time anyone has ever come on this show to stop somebody from doing something,” Kimmel told Romney, after complimenting him on his “big hands.”

From the mocking of a disabled reporter to suggesting Fox News anchor Megyn Kelly was on her period to calling John McCain less than a war hero, Romney said he became more and more fed up with Trump over time. But the “straw that broke the camel’s back” was when Trump pretended not to know who David Duke is.

Because Trump “can be very, very vicious,” Kimmel told Romney “if he is elected president, you’re going to have to move,” adding, “you know that, right?”

“That’s probably the case,” Romney admitted. As he did in his speech last week, Romney refused to endorse just one of Trump’s rivals but instead said he believes they should all stay in the race in an attempt to deny Trump the delegates he needs to reach the nomination.

And while Kimmel tried to get Romney to endorse either Hillary Clinton or Bernie Sanders over Trump, the former GOP nominee refused to go there.

After a break, just for fun, Kimmel had Romney read some “mean tweets” about himself, all of which happened to come from Trump and his vocal supporters.

There was something both awkwardly delightful and delightfully awkward in hearing Romney recite tweets like the one below with no attempt whatsoever to imitate Trump’s voice. To one Trump supporter who called him a loser, Romney remarked, “That’s true, actually. I lost.”

All in all, Mitt Romney has never been funnier—a low bar, to be sure—and he has Donald Trump to thank for that.