Dr. Maniac vs. Robby Schwartz is the 5th book in the Goosebumps HorrorLand series.
Synopsis[]
Robby creates comic strips on his computer. His favorite creation is Dr. Maniac, a weird and wicked supervillian. Dr. Maniac isn't a real doctor, but he sure is a maniac. And now he's on the loose... in the real world!
Meanwhile, seven ordinary kids are now trapped in the popular theme park called HorrorLand. Can Robby survive long enough to find and save them? A hairy situation awaits in Werewolf Village.