007 Iron Man
When Tony Stark was injected with Extremis, it was an act of desperation done to save his life. It was unknown what the untested nanotech virus would do to him. In the end, however, it expanded his mind, enhanced his abilities, and rebuilt his body into a living weapon. Granted, full cybernetic interface with his armor and any nearby technology, he became truly invincible, and nearly unstoppable.