Personalized Monster 5th Birthday T-Shirt. I'm 5! A giant lizard monster towers over a burning city, shouting that it is 5. Cool birthday gift for any five year old! Everyone loves our Custom T-Shirts! Wardrobe essential for looking good, 24/7. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar. Shoulder-to-shoulder taping. Double-needle stitched sleeves, bottom hem and front neck. Note: greys are a cotton/polyester blend.