Stephen Colbert used his opening monologue Monday on “The Late Show With Stephen Colbert” to mock Donald Trump’s tweets about his son’s meeting with a Russian lawyer in 2016, in which he called Donald Trump Jr. “wonderful.”

Colbert zeroed in on Trump’s tweets from Sunday in which he admitted the Trump Tower meeting in June 2016 was actually about getting information on Trump’s opponent in the 2016 presidential election, Hillary Clinton. But first, Colbert took issue with the way Trump described his son, Donald Trump Jr.

“There’s a report in the Washington Post … that Donald Trump is getting worried that the Trump Tower meeting might lead to criminal charges for his son,” Colbert said during the monologue. “He tweeted, ‘Fake news reporting a complete fabrication that I’m concerned about the meeting my wonderful son Donald had in Trump Tower.’ Wonderful son Donald? So he has two sons named Donald? Oh, it’s the same guy. I’m sorry, OK. It’s just weird to hear someone talk about Trump Jr. like that. It’s like someone saying ‘my wonderful disease, ulcerative colitis.’ “

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The now-infamous meeting has been a centerpiece of the question of whether the Trump campaign colluded with Russia to interfere with the presidential election in Trump’s favor. Trump Jr. met with Russian lawyer Natalia Veselnitskaya on June 8, and was joined by Trump’s son-in-law, Jared Kushner, and his former campaign manager, Paul Manafort, who is currently on trial for financial fraud.

Colbert continued reading Trump’s tweets from Sunday, goofing on the way Trump twisted the situation to make the meeting sound like it wasn’t a big deal — but also to maintain that he knew nothing about it.

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“Trump continued his tweet-fession, ‘This was a meeting to get information on an opponent — totally legal and done all the time in politics. And it went nowhere. I did not know about it.’ OK: ‘Totally legal, actually great, everybody does it, I wasn’t there, put my son in jail.'”

The worst thing about the tweets, Colbert said, was the fact that they show Trump himself exposing the fact that the administration initially lied about the focus of the meeting. As Colbert pointed out, Trump now admits the meeting was to get dirt on Clinton — “also known as collusion,” Colbert said.

“Remember, when news of the meeting first came out last year, the official story was that it was primarily about the adoption of Russian children,” he said. “And now we know that it was primarily about Russian adoption in the same way ‘Silence of the Lambs’ is primarily about lambs.”