It's credited to the Hex Girls, the fictional band within the film, but instead of using Jennifer Hale, Jane Wiedlin and Kimberly Brooks, the (singing) voices of the characters' within the film, they were replaced by Terry Wood, Angie Jaree and Gigi Worth. In light of this information, it cannot be considered a canon song within the Scooby-Doo universe as it has never been performed by the band themselves.