Washington (CNN) Priorities USA, Hillary Clinton's top-dollar super PAC, will begin airing an ad this week that compares Donald Trump's rhetoric with the "hate" that led to the 1998 killing of Matthew Shepard.

"I know what can happen as the result of hate," Shepard says. "So when I see the hate that Donald Trump has brought to his campaign for president, it terrifies me."

The ad features what have now become Trump's greatest hits for the Democratic super PAC: When Trump said that he'd like to "punch (a protester) in the face" in February and when he mocked a disabled reporter in July.

"Words have an influence, violence causes pain, hate can rip us apart," Shepard says looking into the camera. "I know what can happen as the result of hate, and Donald Trump should never be our president."

Speaking on behalf of the Trump campaign, Chris Barron, the co-founder of the LGBT conservative group GOProud, said that he has "nothing but respect for Judy Shepard" but that the ad is "unbelievably disingenuous and absolutely incorrect" in its implication that Trump is biased against the LGBT community.

"This is an attempt to scare gay voters into not even considering Donald Trump," Barron said. "This ad is absolutely false and it is completely and totally flies in the face of what we have seen in this entire campaign."

Barron added that it is "unfortunate" that Judy Shepard "decided to do this."

Shepard was found tied to a fence, beaten, burned and left in a comatose state with a fractured skull in Laramie, Wyoming, in 1998. Witnesses said the two men who were later charged with his death lured Shepard to their truck by pretending to be gay.

Matthew Shepard's death was a seminal moment in the gay rights movement and led Congress to pass the Matthew Shepard and James Byrd, Jr., Hate Crimes Prevention Act.

Priorities USA plans to spend close to $8 million on the new ad, a spokesman said.

With three weeks to go until Election Day, Clinton and her allied groups have so far dominated the airwaves, making up 75% of total ad spending for the 2016 presidential race.

Priorities USA, according to media tracking firm Kantar Media/CMAG, has spent $84 million on ads. That is 25% of all ad spending for the 2016 race.