Vice President Kamala Harris repurposed former President Barack Obama's suggestive dig at Trump over what Obama called his "weird obsession with crowd sizes" while speaking at the Democratic National Convention last month.
"Here's a 78-year-old billionaire who has not stopped whining about his problems ..." Obama said in the clip used in the ad, just before a clip of Trump at rally plays.
"Ooh, she had a big crowd! Ooh, that crowd," Trump said in the snippet, mocking news reports about turnout for Harris.
"This weird obsession with crowd sizes... it just goes on, and on, and on," Obama says as the ad returns to him, followed by shots of small Trump crowds and sounds of crickets chirping.
"America's ready for a new chapter. We are ready for a President Kamala Harris," Obama says.
The Harris campaign said the ad, titled "Crowd Size," will air on Fox News the day of the debate because "Trump is known to watch" the network.
The 30-second ad is set to air nationally on cable news and in local West Palm Beach and Philadelphia markets.