Stephen Colbert showered thanks on Donald Trump, his "Late Show" guest, Tuesday night.

"I want to thank you not only for being here but for running for president," Colbert told the GOP front-runner. "I'm not going to say this stuff writes itself, but you certainly do deliver it on time every day."

Colbert's gratitude for Trump's comic assistance was well-placed. Peppering Trump with questions and wisecracks during his appearance, the CBS host reduced the usually domineering Trump to straight-man status, an unaccustomed role Trump performed with grace.

Bringing up Trump's proposal to build a wall between the United States and Mexico, Colbert offered his own  mocking version of a way to bar illegal immigration: Two walls, and in between them a moat filled with fire and fireproof crocodiles. "Is that enough?" Colbert asked.

And focusing on Trump's insistence that Mexico would pay for the wall, Colbert drew him into a role-playing exercise -- a phone call where "you're you, and I'm the president of Mexico."

Colbert noted that Trump is leading the field while he vows to finance his campaign out of his own pocket.

"The Republican Party has been a big pusher of the idea that money is speech, and you're a $10 billion mouth," said Colbert. "You're their worst nightmare."

"I think the establishment in the Republican Party probably isn't that thrilled," he agreed.

Trump repeated his contention, as a former heavy campaign donor, that candidates who accept major contributions are typically "owned" by those donors once in office.

"You gave them a big contribution and you want something and all of a sudden they've very receptive," he said. If you didn't make a healthy gift, "believe me, you get the cold shoulder."

Colbert asked if Trump really wants to be president: "If you actually got the gig, would that be a step down for you? You know what the pay is like, right?"

Trump replied that he is running "not because I want it, but because I think I can do a great job."

When pressed on his past contention that President Barack Obama wasn't born in the United States, Trump deferred.

"I don't talk about it anymore," he said.

But he was gung-ho for a game that called for guessing who in the past had made certain outlandish remarks: Trump or the comic blowhard Colbert played for a decade as host of "The Colbert Report."

Trump or Colbert? "Medicare is like a nice pair of cufflinks. Nobody wears cufflinks anymore."

"That's you," said Trump. Correct.

Trump or Colbert? "It's freezing and snowing in New York. We need global warming."

"I think it's you," Trump hedged, "but it's close to being me."

It was Trump.

And finally: "The real strong have no need to prove it to the phonies."

"It's not me," said Trump after a pause. "It COULD be you."

"It's not me, either," Colbert said. "It's Charles Manson."

"Ooooo," said Trump.