While most mutants manifest their powers during puberty, Rachel Argosy, a musical teacher from Twin Forks, Maine, had already passed her twentieth birthday when her skin turned blue. Apparently, the delay was caused by her having survived childhood meningitis. The change of her skin tone wasn't the only change, however. Whenever musical instruments were played in close vicinity to Rachel, "weird things" would happen. She could, among other things, use the music to levitate herself, create hallucinations or manipulate emotions.
Not out to harm anyone with her newfound abilities, Rachel continued to teach music. Already well-liked before she manifested her powers, Rachel became tremendously popular with the students attending Twin Fork High School, who soon nicknamed her "Rhapsody." However, the parents were not too fond of an overt mutant teaching their children and, after several complaints and a hearing in front of the school board, it was decided to terminate Rachel's employment.
Two days later, Harry Sharp, the biggest supporter of her being fired, was found dead in his home by his wife. Apparently, his heart had just stopped. When Mrs. Sharpe looked out of the window, she saw Rhapsody lurking outside and she immediately assumed that the blue-skinned mutant had killed her spouse. Rachel was hunted by the police but evaded them several times, thanks to her powers. Eventually, the local authorities asked the governmentally sanctioned X-Factor for help, and Quicksilver and Multiple Man were dispatched to Twin Fork to deal with the crisis.
Apparently, Rhapsody has been released from prison rather recently, for a woman matching her description was spotted in San Francisco. She appeared among a crowd of mutants protesting for equal right rights in response to the "Human Now! Coalition" proposition to legislate when and how mutants would be allowed to breed. [Dark Avengers/Uncanny X-Men: Utopia] Her current whereabouts and activities are unknown.