Personalized Dog and Mouse- Best Friends Toddler T-Shirt. Show off your bestie with Dog and Mouse- Best Friends Toddler T-Shirt - Royal, from the children's book "Dog and Mouse" by Michelle Nelson-Schmidt. A toddler-soft cotton tee in look-at-me, big kid colors. 4.5 oz., 100% combed ringspun cotton. White is sewn with 100% cotton thread. Topstitched rib crew neck. Double-needle stitched sleeves and bottom hem. Shoulder-to-shoulder taping.