Personalized Purple Monster Youth T-Shirt. Purple monster Youth T-Shirt - Kelly Green. This adorable purple monster would love to be a design on any child's t-shirt. Make him a part of your family today. 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.