Stephen Colbert put Donald Trump on blast on Wednesday after the president’s not-so-“reassuring” call for Americans to “BE COOL” just before he pumped the brakes on his sweeping tariffs.

The “Late Show” host played a clip of Trump who — when asked about his urge to chill out hours before announcing a 90-day pause on imposing tariffs on most countries except China — said his reversal was due to people “getting yippy”

“Yeah, exactly, Russia was watching Trump tank the economy and going, ‘Yippee!’” Colbert quipped.

The host then turned to a clip of the president boasting that the “biggest day in financial history” took place after markets looked “pretty glum” for several days beforehand.

“That’s a pretty big change,” added Trump on a day that saw the S&P 500 index make its largest gain since World War II.

Colbert swiftly pointed out that “biggest” isn’t the same as “best.”

“That’s why on Mother’s Day you don’t give her a mug that says, ‘World’s Biggest Mom,’” he joked.

Check out more of Colbert’s Wednesday monologue below.