At first, the parents try to ignore the screaming man at the mall telling their children they've been lied to about Santa Claus.

Then it becomes clear he's not going to stop.

"Kids, I want to tell you today that there is no such thing as Santa Claus," the man tells people waiting in line for Christmas photos at the Westgate Mall in Amarillo, Texas. "Santa Claus does not exist. The Christmas season is about Jesus.

"The man you're going to see today is just a man in a suit dressed up like Santa."

The shouting man is David Grisham, an evangelical street preacher from Anchorage, Alaska, who has shouted his sermons at people across the country for nearly a decade.

On Saturday, his unwilling audience was a group of families at Westgate's seasonal Christmas village.

Grisham paid no heed to calls to "chill out" from parents — and as his sermon picked up momentum, things were about to get ugly. "Don't lie to your children and tell them there's such a thing as Santa, when you know in reality that there are no flying reindeer, there is no workshop at the North Pole … that you buy all the gifts and put them under the tree."

A girl in a Santa hat stared, wide-eyed. Other children shot confused looks at their moms and dads. And a few parents decided to take action.

A man in a blue T-shirt approaches. He's so close to Grisham that the pastor's cellphone camera captures only his torso. "Stop," the man says, speaking over Grisham. "Stop. Stop. Stop. Stop. Stop."

This kind of conflict is not foreign to Grisham, the founder of Last Frontier Evangelism. He travels the country with his wife, spreading the gospel to people who are, for the most part, minding their own business.

On Saturday, he whipped out his cellphone camera to record his Santa truther episode, hoping a viral video would help spread the gospel.

He's claiming victory. The video has been seen more than 2 million times. As an added bonus, mall officials say he's not banned from the mall.

Grisham said he's planning to do the same thing at other malls before Christmas.

"If Santa Claus was a cartoon caricature like Mickey Mouse and everybody knew that it was fake, and no one thought it was real, I'd be fine with it," he said. "But when you start telling kids that Santa Claus is real, it now becomes idolatry. I'm going after it because it's idolatry."

He's not just "going after" Santa Claus metaphorically. In 2010, he videotaped a mock execution of a Santa Claus piñata. "What you can't see," he told his listeners, "is that we shot Santa in the face."

He realizes the tactics strike emotional chords. So he wasn't surprised when he found himself surrounded by angry parents at the mall.

One started pushing him, he said, and on the video he tells the man to stop assaulting him. Nearby, he could see mall employees on their radios, asking for security guards to come. It was time to go.

But first, he offered a parting shot: "Kids, there is no Santa. Santa's not real. Your parents are lying to you. Don't believe it.

"Y'all have a nice day."