(Bob Quast/YouTube)

The U.S. Senate race in Iowa appears to be quickly turning into a competition for which candidate can make the quirkiest campaign ad.

Two weeks ago, Republican Joni Ernst unleashed the "Squeal" ad, in which the Senate candidate compared her experience with castrating hogs to "cutting pork" in Washington.

But Bob Quast, who is running as an independent, may have her beat.

"If you are the sexual predator and sociopath who murdered my sister Lynnette and you come to my front door to do harm to my girls, I'm going to use my Glock [pistol] to blow your [testicles] off," Quast says.

That statement comes 15 seconds into Quast's "spoof" web video on YouTube.

Quast, a former US Army contractor, didn't consider himself a true candidate in the race until the video went viral, he told ABC News today. Quast paid his neighbor $868 to shoot and edit it for him, he said, adding that he plans to release more videos using the donations he receives on his website.

"Before this video, people didn't know who I was. Now every person out there knows who I am," Quast said. "They may think I'm crazy; that's all right. Once they see my next videos and know what I stand for, they won't think I'm crazy."

Despite the happy music playing in the background, the reality behind his threat to shoot were it counts is actually why Quast is making his long-shot run in the first place.

Quast's sister, Lynnette Craft, was murdered and dismembered in Ohio by her husband, Thomas Craft, in 1999. He was sentenced to 12 years in prison in 2000 and released in 2011.

Quast says he is living in a home purchased by Thomas Craft's parents.

Before Craft was released, The Toledo Blade reported on Quast's grassroots campaign to keep Craft from leaving Ohio after his release from prison.

Quast said he and his family have been pushing for legislation called Lynnette's Law that would make it a federal crime for convicted killers to cross state lines. It would also make it a federal crime to use the Internet to plan and commit murders.

Quast said he wrote 545 politicians pushing them to enact Lynnette's Law on an emergency basis.

"For three years, I've been chasing my congressman, Bruce Braley, about this," Quast said. "Now, I'm his competition."

Quast said he wants to make it clear that the YouTube video is a "spoof ad."

"People have gotten the wrong idea about that segment of the video," he told ABC. "The reality is, if you're one person out of seven billion and your name is Tom Craft, then if you come through my front door I'm not going to kill you - I'm going to …. " he said, reiterating his specific threat.

Quast does take a jab at the Democratic Senate candidate, Rep. Bruce Braley, for a comment he made last month at a fundraiser about GOP Sen. Chuck Grassley of Iowa.

Braley warned that if Republicans retook control of the Senate, then a "farmer from Iowa who never went to law school" could be chairman of the Senate Judiciary Committee, a reference to Grassley.

As for Quast, he says in the ad, "Please accept my open invitation for a public debate prior to our June 3 primary. I'll leave my gun at home, as long as you agree to leave your elite law degree in D.C. We'll just use our brains to debate your reckless laws and taxes like Braleycare."

Quast says in the video he is running because "term limits for Congress need to become the 28th Amendment to our U.S. Constitution." He also brandishes his handgun before saying "even a baby" knows the Constitution includes the Second Amendment.

Braley, Ernst and Quast are all running for the seat occupied by Sen. Tom Harkin, D-Iowa, who is retiring. Rep. Braley's campaign did not immediately respond to requests for comment.