Personalized What if we have fun Youth Long Sleeve T-Shirt. The Whatif Monster realizes that trying new things can be fun. What if we have fun Youth Long Sleeve T-Shirt - White, from "Jonathan James and the Whatif Monster" by Michelle Nelson-Schmidt. youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)