Personalized Lucky Unicorn Youth T-Shirt. Cute St. Patrick's Day Youth T-Shirt - White with magical, green Irish unicorn and shamrocks says LUCKY. Luck O' The Irish unicorn lover novelty gift for parades and Irish St. Paddy's Day parties. 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.