Personalized Hippo 1st Birthday Women's Plus Size 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! 100% combed ringspun cotton premium jersey (CVC Colors are 60/40 combed ringspun cotton/polyester)