David Schultz was the ultimate bad guy in professional wrestling. He said what was on his mind and he played the part to perfection.

"You want them to think you’re the baddest, meanest bastard to ever walk the street," Schultz told Viceland’s documentary staff.

But what happens when a reporter puts your craft to the ultimate test?

In the latest episode of Dark Side of the Ring, ‘Dr. D’ as he is also known, tried to protect the secrets behind the wrestling business by making a reporter feel his wrath.

You can watch Dark Side of the Ring: David Schultz & The Slap Heard Round the World tonight on Crave at 10 p.m. ET, 7 p.m. PT.

When ABC News "20/20" reporter John Stossel set out to reveal the truth about professional wrestling in the mid 1980s, his investigation led to an interview at Madison Square Garden backstage with Schultz.

‘People thought it was real and I don’t like people being bulls***ed," Stossel told Viceland.

The interview wrapped up with Stossel telling Schultz that he thought wrestling was fake. Dr. D replied with a couple of slaps to the head of the ABC reporter.

"He told me he thought it was fake," Schultz told Viceland, "I showed him it wasn’t fake.

The incident singlehandedly changed both the business and the trajectory of Schultz’s career.

"The training that David Schultz got centred on one thing; always protect the business," wrestling promoter and historian Jim Cornette told the crew.

Never give away any of the secrets.