A lot of Tony's actions in Superior Iron Man are just plain terrifying. For starters, there's infecting San Francisco with a technological virus, his speech to Daredevil about how he's been "a god playing human", and using his endo-sym armor to keep Daredevil pinned down so he can wipe his memories!
Mallen's death in the Extremis storyline. After Iron Man trashes him, he desperately tries to choke him, forcing Stark to blow a hole in his chest in self defense. After that, he still keeps going. Iron Man reacts by blowing his head off with the repulsors and then... THE HEADLESS BODY TRIES TO STAND UP AND KEEP FIGHTING. It takes a couple of angered kicks (as Stark is furious for having to break his Thou Shalt Not Kill policy) for Mallen to finally stay down.