Has there ever been a real life case of a Jekyll and Hyde like aggressive disorder in the world?

Two of the most iconic split personality cases in my mind for aggression are Dr Jekyll and Mr Hyde, and The Incredible Hulk, or a.k.a Bruce Banner in the old Marvel Comics. Now while I realize turning green, growing an extra five feet and becoming strong enough to bench a tank is slightly far fetched, has there ever been a doented case of a split personality disorder in which the alter ego is extremely aggressive, like the Hulk or Mr Hyde, and that the transition was perhaps triggered by some kind of emotional stress or any other kind of factor for that matter. Any kind of case study reference, or simply a name that I can follow up for myself would be greatly appreciated.