'Game Of Thrones' Star Jason Momoa Once Sent Showrunner To Hospital With Slap Game

Jason Momoa broke hearts earlier this week when he shaved his beard but was breaking bones years ago on the set of Game of Thrones. Literally. The actor who once played Khal Drogo on the popular HBO series broke the showrunner while playing the slap game.

"Jason was one of our favorite people ever on the show, and very strong. And that's not TV makeup -- in real life, he's just a big, strong dude," Game of Thrones showrunner David Benioff told ET.

"So, I'm looking at Momoa and Momoa's talking about beating someone at the slap game," Benioff went on. "I was like, 'I'll take you at the slap game.' I was like, 'I'm going to challenge the Khal, because if I beat the Khal, I am the Khal.'"

This all lead to a few beers being consumed on both ends of this challenge, probably prompting Benioff to feel a little bit of the ole alcholic courage. He went ahead and issued a challenge to Momoa in this slap game which he would quickly regret. "I looked over and his hands were bright red," Weiss shared. "He was still going, and that was when all of us decided to put our conversation on hold to watch this contest."

Still, Benioff didn't want to give up so easily. "I looked in Momoa's eyes, I saw no mercy there," Benioff said. "But I wouldn't quit, because, you know, I had my pride. I had my dumb pride."

By the next morning, Benioff saw the major error in his decision. His hands had "doubled in size," he said. After heading home, Benioff asked his wife Amanda Peet to take a look at this hands. "Her diagnosis was that Jason Momoa had squished my hands," Benioff said, adding that he had a few X-Rays to be careful. "So, it just goes to show, don't challenge the Khal."

Probably shouldn't challenge Aquaman, either.

Game of Thrones airs Sundays at 9pm ET on HBO.