The Enervator was developed by Tony Stark for medical research, as a new surgical technique. It was first used to save Happy Hogan's life; without it, the cobalt ray machine couldn't generate enough energy. Although it was never tested, it kept Happy alive, but also multiplied his strength and power a hundred-fold, even altering his facial structure and eventually turning into the Freak.
Iron Man chased him and managed to lure him to his factory, where he tricked him into walking into a maximum power burst of the Enervation Intensifier, hoping it would turn him back to Happy Hogan.
The Enervation Intensifier was again used by Tony Stark to revert the Freak back to Happy Hogan.