Personalized Hippo 1st Birthday Toddler Dress. 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! Your little one will be adorable and comfortable in this 100% combed ringspun cotton 1x1 baby rib dress!