Former Vice President Joe Biden hasn’t formally announced he will run for president, but Donald Trump is already treating him like a potential 2020 contender.

The president pounced on Biden’s slip of the tongue at a dinner in Delaware Saturday night that reportedly drew a standing ovation from attendees who collectively interpreted the gaffe as a signal the former VP will announce his third White House bid.

“I know I get criticized. I’m told I get criticized by the new left,” Biden said at the First State Democratic Dinner in Dover. “I have the most progressive record of anybody running for the — anybody who would run.”

The crowd cheered, but three days later, Trump ridiculed.

The president tweeted that the longtime Democratic senator “got tongue tied over the weekend when he was unable to properly deliver a very simple line about his decision to run for President.”

He then advised his followers to “Get used to it.”

Why? According to Trump, Biden, who has drawn praise from lawmakers and officials of both parties, is “another low I.Q. individual!”

The Saturday remark was the second time in less than a week that Biden has signaled he will run.

And Trump’s tweet is a signal he views Biden as a serious threat. He has lashed out at other Democratic candidates, like former Texas Rep. Beto O’Rourke, but been mum on others, like Minnesota Sen. Any Klobuchar.

Last week, Trump mocked O’Rourke for moving his hands frequently while speaking publicly. He suggested it means the former lawmaker might be “crazy.”

The president was back on Twitter on Monday morning after a weekendlong rant on his preferred social media platform that saw him suggest “Saturday Night Live” should face a federal investigation for its spoofing of him. The president also tweeted calls for special counsel Robert S. Mueller III to not issue any report when his 2016 Russia election meddling probe ends, and other posts painting himself as a victim and his foes as villains.