Republican presidential nominee Donald Trump speaks during a campaign rally in Novi, Mich., on Sept. 30, 2016. (Jewel Samad/AFP/Getty Images)

Hillary Clinton’s campaign on Friday mocked Donald Trump over his appearance in a Playboy adult film, hours after Trump had sought to discredit a former Miss Universe by alleging she had appeared in “sex tape.”

"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," Clinton spokesman Nick Merrill told a group of reporters stationed outside a Clinton fundraiser in Miami Beach.

Merrill, who regularly travels with Clinton, added that he had not seen the film in which Trump makes a brief appearance.

Trump faced scrutiny Friday after he attacked former Miss Universe Alicia Machado in several early-morning statements on Twitter, where he accused her of appearing in a "sex tape," among other things. Such a tape does not appear to exist; Trump appeared to be referring to racy — but not pornographic — footage from a 2005 reality show in which Machado appeared.

At the Sept. 26 presidential debate, Hillary Clinton knocked Donald Trump for his treatment of former Miss Universe Alicia Machado. Here's what you need to know about Machado. (Monica Akhtar/The Washington Post)

Machado, who is supporting Clinton, has been at the center of a now five-day-long controversy over denigrating public comments Trump made about her weight in 1996, which the former secretary of state highlighted during Monday's presidential debate. Clinton and her campaign used Trump's attacks against Machado to question Trump's temperament, characterizing him as petty and "unhinged."

On Friday afternoon, BuzzFeed News uncovered an explicit Playboy video from 2000 in which Trump made a cameo. The film, titled "Playboy: Video Centerfold" featured nude women in sexual positions. The GOP nominee made a brief appearance in the film, according to BuzzFeed, and did not appear in any pornographic scenes.

The cover of the VHS tape advertises the "Bernaola Twins," Darlene and Carol Bernaola, two Playboy models.

Speaking at a raucous late-afternoon rally in Coral Springs, Clinton said Trump’s tweets were part of a meltdown.

“Who gets up at 3 o’clock in the morning to engage in a Twitter attack against a former Miss Universe?” she asked incredulously. “Really, why does he do things like that?”

Clinton told the crowd that Trump’s behavior was “unhinged” and was further evidence that he is “temperamentally unfit to be president of the United States.”