Here’s the perfect Halloween onesy costume for your baby –the Monsters University Mike Costume for Infants. Your baby will be perfect as MU Mike with the adorable one eye and smiling mouth with less-than-perfect teeth. The cute grey fin-like horns are picked up by three cute grey toenails. Overall, your baby will rock this lime green costume. The jumpsuit is made of 95% polyester and 5 percent cotton. Included, too is a foam character overlay, a screen printed hat and a pair of booties.