She mainly has very light brown fur with a splotch of dark brown fur on her back. Her ears are short and rounded at the end, and colored dark brown. She has very light beige on her muzzle that ends in a tip between her eyes. She also has some on her paws that end in a wave, and on her stomach that start round at her neck and end at the edge of her stomach, and also has it on the tip of her tail. She also wears a magenta collar with light pink hearts around it.
Cupcake is a sweet puppy, but she can be tough when she needs to be. Cupcake is adventurous, playful and fun-loving. She loves Cookie as a mother. She is good friends with Patches and Rebound. She also mentions that she likes to chew on stuff.
Following her arrival at Shelter 17, Cupcake and Cookie became very attached to each other, with Cupcake calling her "Cookie Mommy." Unbeknownst to Cupcake, Cookie was actively preventing her from being adopted. After Cupcake was accidentally nearly sent to the dump, Cookie took her to Shelter 52, telling her she had to be adopted. Although sad at first, after Cookie told Cupcake how wonderful having a family was, she happily went into the shelter, but not before giving Cookie a farewell nuzzle and telling her she loved her. Ironically, Cupcake was soon after adopted by Cookie's owners, and the two were joyfully reunited.
In "The Ruff Ruff Bunch", Cupcake almost joined the Ruff Ruff Bunch with Patches and Rebound, but she and Patches stayed behind and then alerted the Pound Puppies that Rebound was trapped on a train heading to Tierra del Fuego. She was last seen relaxing with Patches at the groomers'.