Personalized Little Sister Unicorn Youth T-Shirt. Little Sister Unicorn - A cute little sister unicorn prances with a heart on her cheek in a rainbow filled sky. Cute gift for any little sis! 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.