While watching TV, P.J. and Max see the trailer for an upcoming horror flick, "The Mutilator on Main Street: Part 7," which Pete encourages P.J. to go see, thinking it will make a man out of him. However, Goofy is at first reluctant to let Max go and see it, because whenever Max gets scared, he gets a bad case of the hiccups. However, after Max persuades Goofy that nothing scares him anymore, Goofy lets him see it with P.J. Unfortunately, the movie proves to be scary enough to traumatize both P.J. and Max, with Max getting the hiccups.
Knowing P.J. would be too scared to walk home by himself, Max asks him if he'd like to spend the night. When P.J. calls Pete to ask permission to stay over, Pete cruelly jokes that the movie is based on a true story, and that the real Mutilator was on the loose. Later, Pete decides to have fun scaring P.J. and Max by pretending to be the Mutilator.
Pete goes over to Goofy and Max's house and begins to make all kinds of noises, which cause Max and P.J. to become scared. When Pete peeks into Max's bedroom window and lightning crashes, the boys thing that the Mutilator has come to get them. They inform Goofy about the noises, who then decides to go and investigate. Goofy is accidentally locked out of the house, and while he tries to find a way back inside, the boys think HE is the Mutilator.
When Peg catches Pete sneaking in and finds out he was scaring Max and P.J., she makes him go back and apologize. When he sees Goofy covered in mud, he becomes scared and accidentally hit his head on a branch hanging from Goofy's tree and knocks himself out. When the phone line cuts out, Max and P.J. try going over next door to call the police, and find the unconscious Pete, assuming him to be a dead body. They run back to the house and boarded up the front door. Meanwhile, Goofy enters the house through the basement window. As he stumbles around in the darkened basement, Max and P.J. assume that the "Mutilator" is down in the basement, and they run up and hide in the attic.
When Goofy becomes stuck in the basement, he uses a chainsaw to cut down the door. P.J. and Max both come down with a case of the nervous hiccups. Goofy then goes into the kitchen to make a replacement sandwich after the cat ate his first one earlier. Goofy falls back down into the basement after slipping on some of the food he dropped on the floor. Max thinks that the Mutilator has got his dad and goes down to rescue him. When he sees a shadow move across the living room, P.J. and Max throw a blanket over Goofy, assuming that it's the Mutilator instead, and start beating him with a tennis racket and a fly swatter. All three of them fall into the basement. P.J. flips on the light switch, and it is revealed to the boys that the "Mutilator" is actually Goofy, who tells them that the Mutilator isn't real!
Later, Max and P.J. find out that the "dead body" under the tree is actually Pete. We see Peg wrapping gauze around his head the next morning. Goofy then shows up wearing a mask and carrying a chainsaw. Pete thinks it's the Mutilator, and jumps up in fright, only to hit his head on the tree branch yet again. Goofy then proceeds to cut off the branch with the chainsaw.
- When P.J. says the Mutilator ate Goofy's cat, Waffles, the colors on his mouth and tongue were mixed up.
- When Peg is awake after she hears Pete cackling and laughing, she's in the same pink shirt instead of her lavender pajamas.