Why are parents hurling slices of cheese at their kids?
It's all part of the "Cheesed Challenge," started by a dad from Michigan who posted videos of himself throwing slices of cheese at his son Charlie.
Some of the kids think it's funny, others are baffled.
But the challenge is also leaving some kids startled and less than thrilled, leading to some serious blowback on social media.
"One of the dumbest things I have seen," read one tweet.
Chrissy Teigen even chimed in, writing, "I love a prank as much as anybody but I cannot get myself to throw cheese at my adorable, unsuspecting baby who has all the hope and trust in the world in me."
Pediatrician Dr. Dyan Hes told Inside Edition that Teigen's instinct is a good one.
"I think it's awkward and uncomfortable for the child," she said of the challenge. "I think the baby will really be startled and worried that it's gonna happen again and again and that might make the baby nervous or fearful.
"Why would you want to do that to a baby?" she added. "A baby's innocent."