*She is allergic to dogs, but tolerates it for the sake of Shaggy and Scooby-Doo. She was at one point possessed by a demon until her protoplasm was freed and returned to her body.

Mary Jane is a woman with a light tan, with long, curly blonde hair, and brown eyes.

When she met Shaggy, she wore an orange shirt and a long denim skirt. Prior to the Demons' attack, she had switched to a sparkly pink, long-sleeved top with a notably short hem, exposing her belly and back, and brown shorts. After being possessed, the demon in control of her body switched her outfit to a red bikini top covered by a lace yellow vest, with the tails parting to her sides, once again exposing her midriff, and jean-shorts.*