Barbie in Rock 'n Royals Singing Erika Doll Transform from princess to pop star with this singing Erika doll from Barbie in Rock 'N Royals Push her arm to swing her guitar and activate a fashion transformation and musical moment! Erika's skirt twists around, magically transforming her look from a princess gown into the rock star outfit! Doll sings along to one of two musical clips from the movie as she transforms! Pull her elbow to transform back into a princess With household brands like Barbie, Hot Wheels and Fisher-Price, Mattel has been at the helm of creating fun and adventure for children since 1945. The company, started by Harold Matt Matson and Elliot Handler, believes in the importance of play in a childs life and reinforces that with every Mattel toy.