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?"