Dr. Maniac vs. Robby Schwartz (Goosebumps HorrorLand #5‪)‬

Robby creates comic strips on his computer. His favorite creation is Dr. Maniac, a weird and wicked supervillain. 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. . . .