Even Biden had to chuckle at Trump’s latest taunts, although the Democratic nominee opted against saying anything when a reporter asked him later Sunday about the president’s demand.

“He’s almost ...,” Biden said before interrupting himself. “No. I have no comment.”

Later, the Biden campaign reconsidered.

“Vice President Biden intends to deliver his debate answers in words. If the president thinks his best case is made in urine he can have at it,” said Kate Bedingfield, Biden’s deputy campaign manager. “We’d expect nothing less from Donald Trump, who pissed away the chance to protect the lives of 200K Americans when he didn't make a plan to stop COVID-19.”

Normally, Biden’s campaign wouldn’t respond to Trump, calling his comments a distraction or a case of serial deception or both. Biden, for instance, last week declined in recent days to say whether he still opposes adding more members to the Supreme Court and Bedingfield also declined to comment on the idea of Trump not agreeing to peacefully transfer power if he loses the race to Biden.

But Trump’s remarks about Biden using drugs and needing a drug test were too weird to pass up for the campaign, especially because advisers want this process story to play out because it shows just how much trouble Trump feels he’s in concerning the debates.

Trump for months has been portraying Biden as weak and 'sleepy,' but setting expectations so low heading into a debate all but ensures the former vice president will more than deliver and has left Trump bracing for a presidential self-own.

So Trump recently test-drove his new attack line, telling a crowd on Sept. 19 “don't underestimate {Biden] .... They give [Biden] a big fat shot in the ass, and he comes out, and for two hours, he's better than ever before.”

For the record, Biden's longtime advisers and observers note that he doesn't even drink alcohol.