“As his approval rating gets lower, somehow his engine fills up with more and more self-esteem,” Kimmel said, and rolled footage of Trump at a rally this week declaring himself the “GOAT” or “greatest of all time.”

“It’s so sad,” Kimmel said. “He might be the most insecure person in the history of the world. Remember when we all used to hate people who talked like that? ‘I’m the GOAT.’ This one we made president.”

Kimmel also ripped Trump for his “truly appalling” comments about Los Angeles and San Diego being “taken out” by Iran.

“I know he says a lot of crazy things. I know this is something we’ll forget about by Thursday when he accidentally swallows a baby at a rally or whatever the hell he does next,” Kimmel said. “But, that’s one of the craziest, most indefensible statements I have ever heard even this maniac make.”

The White House claimed Trump was not calling for Iran to bomb those cities but was saying he wanted to prevent that.

Kimmel said there might be a reason Trump has it out for California, then rolled footage of Gov. Gavin Newsom (D) earlier this year greeting first lady Melania Trump with a kiss.

“Our governor got farther with his wife than he has in 15 years,” Kimmel said. “That’s right. And she’s been California dreamin’ ever since.”

See more in his Tuesday night monologue: