In the episode Run Doc Run!, Doc almost steps on Dart during a practice run with her father Mr. McStuffins. Doc sprains her ankle and she takes Dart with her in order to find her missing owner and as Dart had an injury similar to Doc's.
Dart is a white unicorn with a teal mane, tail and a gold-colored horn. She has blue eyes and is lightly tanned.
- Her looks are similar to that of the G2 or G3 My Little Pony toyline.
- Her voice actress also voiced characters such as Blossom in The Powerpuff Girls, Tanya in An American Tail: Fievel Goes West, Glitter in Kidd Video, Abila in Jackie Chan Adventures, Cecilia in Peter Pan and the Pirates, Mrs. Larkin and Teri in What's With Andy?, and Faith in Scooby-Doo! Legend of the Phantosaur.