Dr. Maniac Will See You Now Book by R. L. Stine

Richard Dreezer loves reading comic books. He spends a lot of his time at the Comic Book Museum in his neighborhood. He even dreams of being a superhero with strange and amazing powers. But when the insanely devious Dr. Maniac appears in the real world, Richard has his hands full. If Richard doesn't do something fast, everything he knows will be destroyed. But how fo you reason with a maniac? Richard better figure it out fast because the doctor is now in...sane.