February 1, 2007
The Incredible Hulk #400 
In this story, we get the origin of the Leader, a janitor who got caught in a Gamma Ray explosion much like Bruce Banner, but instead of seeing his strength expanded he saw his intellect expand, along with his head. And he also got green skin. Anyway, he decided that world conquest was his destiny, and was behind the plans of the Chameleon in the previous issue. He decides to get more directly involved this time, having created a mentally controlled "Humanoid" that he sends to steal an experimental atomic device designed by Bruce Banner from a transport train. Of course Banner turns into the Hulk and has a great little battle aboard the train with the Humanoid. Eventually the Hulk wins, but ends up imprisoned as Bruce Banner, while the Leader's curiosity about his Gamma Ray mutated brother has been raised for the next year of stories.
Neat little story, building on the background of the Hulk nicely and with one of the great fight scenes of Ditko's comics of the era.