Hartley Rathaway was born deaf, but was eventually cured thanks to research funded by his wealthy father. He then became obsessed with sound and began experimenting with sonic technology later in life. He eventually developed a technique of hypnotism through music, and turned to crime when he grew bored of his lifestyle. He's fought on both sides of the law, sometimes acting as a vigilante, and other times fighting the Flash alongside the other Rogues. He may not possess any superhuman abilities, but his research into sonic technology granted him unique and powerful abilities of mind control, using nearly any object that can create tones. Originally, he employed his mind-control techniques exclusively on humans, but eventually became infatuated with controlling animals as well, including the rats that inhabited Iron Heights prison.