While Apple Stores typically come off as sleek, clean and beautiful, these stores hold many deep and dark secrets that may forever change the people that hear them. Today, one of those secrets has been revealed.

Pee balls. While you may see them as the nice cute and comfortable black seats your kids sit at while they’re trying out Angry Birds in the Apple Store, the employees there know the truth. Ex-Apple Store employee and Reddit user Mister_Rabbit took to the popular website to tell this story:

Going through my old photos from when I worked in Apple retail years ago and came across this gem, the kid’s table piss ball. I had almost forgotten that little tidbit of knowledge I had learned from the job. Apparently when kids are really into a game they will often choose to just pee in their seat without stopping what they’re doing. The result? Squishy black ball seats. I had never really believed that kids would do this until I walked by while they were retiring one of the balls one night.

A number of other users that said they had worked for Apple in retail also commented, confirming that they had been referred to as “Pee Balls” at their stores as well.

“4 years in Apple Retail taught me to never go near the black balls. Our kids table was right in front of the Genius Bar, so when a customer was being a jerk about it being crowded, I’d always offer them to sit on one of the black balls, ” said another user.

Other users reported that the balls were frequently cleaned and that it was part of Apple’s policy to replace any ball that got stained.

So from now on, whenever you go in the Apple Store and are busy thinking of the marvels of modern technology, also remember — kid piss.