Personalized 100 Days Girl Monster Youth T-Shirt. Youth T-Shirt - Black with funny cartoon green girl monster wearing glasses with book, pencils and blackboard says 100 DAYS SMARTER. Cute 100 Days of School gift for book worms, book nerds and book lovers. 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.