Donald Trump plunged deeper into campaign controversy by publicly shaming a former beauty queen for her "disgusting" sexual past.
Then - in one of presidential history’s more bizarre moments - he encouraged Americans to watch a “sex tape” he said would support his case.
However, it later emerged the Republican presidential nominee himself featured in a cameo in an explicit 2000 Playboy video.The day began with a series of 3.20am tweets by Mr Trump that caused outrage, and ended with his rival Hillary Clinton's campaign calling the tycoon an adult film star.
Did Crooked Hillary help disgusting (check out sex tape and past) Alicia M become a U.S. citizen so she could use her in the debate?
— Donald J. Trump (@realDonaldTrump) September 30, 2016
Even many of Mr Trump’s supporters shook their heads at their candidate’s latest outburst, worried it could further hurt him among the nation’s women, many of them already sceptical, and whose votes he needs to win the election.
It came as Mr Trump and his daughter Ivanka appeared in a new advert aimed at women and touting his recently announced proposals for childcare tax credits and paid maternity leave through unemployment insurance.
Mr Trump posted on Twitter at 5.30am: “Did Crooked Hillary help disgusting (check out sex tape and past) Alicia M become a U.S. citizen so she could use her in the debate?”
It referred to 1996 Miss Universe Alicia Machado, a Venezuela-born woman whose weight gain he has said created terrible problems for the pageant he formerly owned.
Unsurprisingly, Mr Trump’s pre-dawn Twitter tirade ricocheted across the campaign trail.
His campaign accused the media and Mrs Clinton of colluding to set him up for fresh condemnation, to which she retorted: “His latest Twitter meltdown is unhinged, even for him.”
‘Cheap lies’
Ms Machado took to Facebook to say his tweets were part of a pattern of "demoralizing women," calling them "cheap lies with bad intentions".
Planned Parenthood said it showed that Mr Trump’s “misogyny knows no bounds”.
And Mrs Clinton said they showed anew why someone with Mr Trump’s temperament “should not be anywhere near the nuclear codes”.
With less than 40 days left in the election, Mr Trump’s broadside threw his campaign into a fresh round of second-guessing the candidate’s instincts and confusion about what to do next.
Shaming Ms Machado over intimate details from her past could be particularly risky as Mr Trump tries to win over more female voters, many of whom dislike such personal attacks.
It also risks calling further attention to the thrice-married Mr Trump’s own history with women.
Mrs Clinton asked what kind of a man “stays up all night to smear a woman with lies and conspiracy theories?”
Even Mr Trump’s most vocal allies seemed at a loss for words.
"He's being Trump. I don't have any comment beyond that," said former House Speaker Newt Gingrich, a senior supporter.
He said Mr Trump sometimes does “strange things,” but that Mrs Clinton lies: “I’ll let you decide which is worse for America.”
Mr Trump did not mention the tweets on Friday evening as he rallied supporters in Michigan.
Instead, he returned to Twitter to invoke Mrs Clinton's famous ad from her 2008 campaign portraying her as the best candidate to pick up an urgent call at the White House at 3am.
He wrote: “For those few people knocking me for tweeting at three o’clock in the morning, at least you know I will be there, awake, to answer the call!”
Ms Machado has been in the campaign spotlight since Mrs Clinton noted on Monday in the first TV debate that Mr Trump had mocked her publicly for gaining weight after she won Miss Universe.
If that was a trap laid by Mrs Clinton, the irrepressible Mr Trump dug himself deeper the next day by saying Machado’s “massive” weight gain had been “a real problem”.
That gave the Clinton campaign the opening it wanted, as her team circulated videos featuring Ms Machado accusing Mr Trump of destroying her self-confidence, just as many voters were starting to cast early ballots.
Mr Trump’s Twitter taunts referred to footage from a Spanish reality show in 2005 in which Ms Machado was a contestant and appeared on camera in bed with a male contestant.
The images are grainy and do not include nudity, though Ms Machado later acknowledged in the Hispanic media that she was having sex in the video.
Then it emerged that the Republican presidential nominee featured in a cameo in an explicit 2000 Playboy video.
In a short clip posted on the website BuzzFeed, Mr Trump pours a bottle of champagne on a Playboy-branded limo on a New York street, surrounded by a gaggle of women.
"There's been a lot of talk about sex tapes today and in a strange turn of events only one adult film has emerged today, and its star is Donald Trump," said Clinton spokesman Nick Merrill.
AP