You never know what you are going to see at the ballpark.

During the ninth inning of the St. Louis Cardinals' 5-4 win over the Kansas City Royals on Friday night at Busch Stadium, fans started migrating to an empty section in right field and took their shirts off.

The game was tied 3-3 in the bottom of the ninth inning when the group of fans made their way to the empty section. About 100 fans first started the movement, and as the game went to extra innings, the entire section was packed with shirtless fans, according to the St. Louis Post-Dispatch.

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Caleb Cummings, a 20-year-old on the Stephen F. Austin club baseball team, came up with the idea.

"I looked at my buddy and said, ‘What if we go up there to right field bleachers and start waving our shirts?" Cummings told the St. Louis Post-Dispatch. "They're like, ‘You know what, that's a good idea.’ We had no intentions of it getting that big — we were just going out there to have fun. We got up there, and we're all standing there, and we're like, ‘Who's gonna do it first?’"

Bryce Bradford was the first to remove his shirt and wave it around, and it quickly drew a crowd.

"He started waving it and going crazy," Cummings said. "So then it just spread, and then there are a few kids in the section next to us who came to join. And soon, I see people from the ages of like 80 years old to kids doing it. Dads coming over with their kids, running over with their shirts off."

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When Yohel Pozo smacked a pinch-hit line drive on a 100 mph fastball to win the game in the bottom of the 11th inning, the shirtless crew in the right-field stands went ballistic. It was the Cardinals' fourth walk-off win of the season.

Cardinals manager Olli Marmol opened his postgame news conference with praise for the energy the shirtless fans brought.

"Whoever started that in right field, I'll do whatever I need to do to make sure they come to every game," Marmol said. "Because that was awesome. Not only them, but everybody that showed up today. That was a fun environment."

The manager said the fans had a real impact on the game.

"It creates an environment where, it’s not only filling this place up, it’s making it a tough place for other teams to come in and play," Marmol said. "That was pretty damn cool. I’ll sign up for that, any day."

The Cardinals (26-18) will look to keep their momentum rolling when they play the Royals (19-26) again in the second game of a three-game series on Saturday.

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