Personalized Unicorn Christmas Youth T-Shirt. Unicorn Christmas - A cute little unicorn wearing a Santa hat uses some unicorn magic to make a sparkling Christmas tree with rainbow decorations. 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.