STILLWATER, OKLA (KOKH) — A bet between siblings turned into a viral moment and a highlight in the game between Oklahoma State University and Houston on Saturday.

Callista Bradford and her brother, Trent Eaton, were attending the game when she bet her brother $10 to go to the empty section of the stadium, take his shirt off, and wave it.

In an interview on Good Day Oklahoma, Trent said he took the bet, thinking at the very least, it would give his sister and his son something to laugh about.

Trent said while he was waving his shirt, another man walked up and asked if he could join. A few minutes later, two more people joined, and soon, a whole crowd had gathered in the section, waving their shirts.

“It blew up more than I could ever imagine,” Trent said. “When it was just the four of us, I thought, ‘Okay, this is cool, there’s three other guys with me’, but then as more and more people started coming, I was like, okay, I’m going to scoot over and give them more room. Eventually, there were guys in the 60s and 70s, there were 9 and 10-year-olds, there were guys who had been to the gym a lot more than I have, so I had to be in the same shot as them on the jumbotron. I was like, alright, you guys have the spotlight now, I’m going to move off to the side a little bit.'”

Callista said this is completely in character for her brother and thought the whole thing was hysterical. Chris’ University Spirit even made shirts and rally towels of the shirt-swinging section and sent some to the siblings.

After the game, Callista didn’t have to pay Trent the $10, instead, he took her out to lunch.