Personalized Hippo 1st Birthday Toddler Long Sleeve T-Shirt. Hippo 1st Birthday! I mean Happy 1st Birthday! A cute, smiling hippo wearing a birthday hat sits in front of a birthday cake ready to blow out the candle. Cute first birthday gift for the one year old! 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.