Personalized I'm Three Mendous Youth T-Shirt. I'm Three Mendous! Pow! Wow! Third birthday comic book style for your tremendous little superhero. Great 3rd birthday present. 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.