Personalized Little Sister Superhero Toddler Long Sleeve T-Shirt. I'm the little sister, and I'm a superhero! Cool gift for any super little sis! A classic for Fall, Winter and Spring, these long sleeve toddler t-shirts are sure to be a staple in your child's wardrobe. Whether layered or alone, this t-shirt is soft yet durable enough to stand up to your toddler's playtime demands.