Personalized 3rd Birthday Monster Youth T-Shirt. 3rd birthday monster. A cute monster holds a bright yellow balloon to celebrate the three year old's third birthday! Great gift for your little monster! Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.