It was when I saw a little boy urinating in a corner of the ball pit that my kids stopped playing in them. That goes for the jungle gym equipment at fast-food restaurants too! And if you've long suspected that ball pits are gross, you're not wrong. University of North Georgia researchers found a ton of bacteria on each ball from a ball pit-- a total of 31 different types of bacteria, and one yeast species. Four types of the bacteria found on the balls are known to cause nasty infections in humans. Also, these researchers looked at ball pits in children's physical therapy facilities, so you can only imagine how much worse the germs must be at the ball pit in your local fast food joint!