Dana White left little for interpretation. If Conor McGregor resorts to his mixed martial arts ways in the mega-fight against Floyd Mayweather Jr., he’s going to regret it for a long time.

“He would have a lawsuit against him that would destroy Conor’s life, and Mayweather would win,” the UFC president said Thursday as the world tour hit Brooklyn’s Barclays Center with a press-conference show for its third stop on the four-city hype machine that finishes in London. “It absolutely cannot happen.

“He would be sued beyond belief if he does anything but hit Floyd Mayweather with his hands to the head and body.”

White said there is language in the contract that would punish McGregor for doing so, though no one has given exact details about what that is, whether it would include a large chunk of his purse or merely result in him getting sued or losing proceeds from pay-per-view buys.

“There is a significant penalty,” Showtime Sports executive vice president Stephen Espinoza said. “It was enough of a financial disincentive.

“Something out of the ordinary beyond what would be a normal ‘boxing’ [action].”

When asked if he would pull out any MMA moves, McGregor said: “We’ll see on the night.”

White repeatedly said “that can’t happen,” when asked if he was concerned McGregor, a UFC champion in two different weight classes who has never had a professional boxing fight, could grow frustrated against the skilled and defensively sound Mayweather and revert to other means to hurt his opponent.

“Any lawsuit is all about damages, and damages on Mayweather if something like that happened would be massive,” White said.

During the first day of the tour in Los Angeles, McGregor taunted Mayweather’s father, Floyd Sr., that if the undefeated 12-time boxing world champion disrespects him, “I might just bounce an elbow off his eyebrow.” Mayweather said he’s not worried about McGregor breaking the rules, saying it’s up the referee to handle it.

“My job is to keep my composure,” Mayweather said.

After all, White pointed out, McGregor is in line to make a ton of money, so why would he risk that? At one point, White suggested McGregor could retire from fighting after this bout, though the UFC boss later said he expects him to return to MMA before the end of 2017. White predicted the showdown could net up to 4.9 million pay-per-view buys, which priced at $99.95, could net nearly $500 million.

“Conor is a bit of a wild man, but he likes money as much as Floyd does,” White said. “He wants Floyd to have all his money, that’s the way to do it.”