A South Korean soccer club has issued an apology after their Sunday game when fans noticed some unusual props placed throughout their stadium. In lieu of fans, FC Seoul placed faux supporters in the stands, which many fans quickly recognized as sex dolls.

The team had placed about 20 of the props in stadium seats near the goal, complete with masks, apparel and signs to present the illusion that real fans were admitted into the game. While FC Seoul apologized for the mix-up, the club insisted that mannequins ordered from the manufacturer are not meant for adult use.

“We are very sorry about the supporting mannequins that were placed during the game on May 17,” reads a translated statement from the club. “These mannequins may have been made to look and feel like real humans but they are not for sexual use — as confirmed by the manufacturer from the beginning. Our intention was to do something lighthearted in these difficult times. We will think hard about what we need to do to ensure that something like this never happens again.”

Buy Sell and Go with confidence at StubHub

The inadvertent act may subject FC Seoul to a fine for violations of the K-League’s rules forbidding inappropriate and/or sexual advertisements. A league official reportedly told the news site OSEN that the matter will be investigated, according to ESPN.

FC Seoul is not the first international sports team to feign supporters at games. One Chinese Professional Baseball League team also placed robotic mannequins throughout its stands – complete with face masks and team apparel – for games this spring before the league announced that up to 1,000 fans can be admitted into stadiums.