As Republicans scramble to shift gears against a new Democratic presidential nominee, a conspiracy theory about President Joe Biden emerged over the past few days, one that purported a kind of “Weekend at Bernie’s” situation involving the president.

Yes, that sounds ridiculous. But after the president‘s announcement that he would no longer run for re-election, the ludicrous claim gained some traction in right-wing circles: that Biden, who tested positive for Covid-19 while campaigning in Las Vegas on Friday, was either dead or severely incapacitated. (Biden’s decision to bow out of the race was not attributed to any specific medical issue.)

Several Fox News anchors cast doubt on Biden’s whereabouts on Sunday. Bret Baier said it was “disconcerting” that Biden had not been seen. His co-host Dana Perino said, “I hope he’s fine. But you can forgive people for wondering if we are really living ‘Weekend at Bernie’s’ right now. Proof of life, please.”

An account associated with Donald Trump’s presidential campaign posted a clip of the exchange on X and implied that Harris was somehow behind the mystery.

On Monday morning, Rep. Lauren Boebert, R-Colo., similarly demanded “proof of life from Joe Biden” in a post on X, adding that he should “discuss if he’s aware that he dropped out.”

Turning Point USA founder Charlie Kirk then claimed on social media platform X that he had a “lead” that Biden was “dying or possibly already dead.” His account later shared a link to an unverified story, attributed entirely to anonymous sources, that Biden had suffered a “full-blown medical emergency.” Right-wing billionaire Bill Ackman also suggested that Biden’s Sunday letter was suspicious because it had a digital signature.

Rep. Keith Self, R-Texas, announced a press gaggle on Tuesday afternoon for the purpose of questioning why Biden hadn’t “been seen since Kamala’s Coup” (despite the demonstrable fact that Biden had been).

The idea that Biden was dead or near death, and that Democrats were somehow hiding it from the public — and from a White House press corps that is voracious for scoops — is deeply unserious. There is no evidence whatsoever that the president was not simply recovering from Covid. But such unfounded conspiracy theories have often found a credulous audience among the right, where claims have long festered that Biden is a puppet of Democratic Party “elites” (a group that somehow excludes the president himself).

Meanwhile, Biden was seen boarding Air Force One in Delaware on Tuesday. White House physician Kevin O’Connor said in a memo released the same day that the president’s Covid “symptoms have resolved.”

Biden is set to speak from the Oval Office on Wednesday about his decision to drop out of the presidential race.