Personalized Big Sister Comic Book Toddler Long Sleeve T-Shirt. Big Sister! Pow! Cool! A big sister is like a superhero, watching out for her little siblings. Cute gift for any big 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.