Personalized Monster 3rd Birthday Toddler Long Sleeve T-Shirt. Cute 3rd birthday Toddler Long Sleeve Tee - White with a funny cartoon purple monster, stars and polka dotted number 3 says THIS LIL' MONSTER IS THREE! A classic for Fall, Winter and Spring, these long sleeve toddler t-shirts are sure to be a staple in your child's wardrobe. Whether layered or alone, this t-shirt is soft yet durable enough to stand up to your toddler's playtime demands.