The Big Scream is an animated special featuring several monsters from the toyline. It first aired on Halloween of 1992, and was produced by Hanna-Barbera studios. It was supposedly going to be picked up for a series, but never managed to do so due to low ratings of the pilot.
The Big Scream begins with Invisible Man, given the name Dr. Henry Davenport, giving an explanation of the events that had happened. He, Big Ed (The Monster), Wolfmon (Werewolf), and Mummy were guards at the Monster Mountain prison, which kept several monsters, including Tyrannosaurus Rex and Cyclops. However, Vampire had a plot to shrink himself down so he could escape the prison. It ended up shrinking the entire mountain and blowing it to California. There, Dr. Davenport and the others found Carrie Raven, daughter of a famous horror writer, and befriended her.
The actual show starts off with Dr. Davenport concocting a potion that will turn him and his three allies into normal-sized monsters. The plan fails due to Mummy, but they discover that they can grow large just by Carrie laughing. They are interrupted by Helga, Carrie's maid, who forces Carrie out of the basement because she's too messy.
Later, Vampire attempts to mind-control a dog, but he fails miserably. The dog attacks Vampire and the evil monsters (Medusa and Swamp Beast), and chases them away to a drive-in movie theater. The actress in the film screams loudly, allowing Vampire, Medusa, and Swamp Beast to grow to their normal height. Medusa steals a car and they drive off to capture Carrie Raven. Helga answers the door, and Medusa turns her to stone. Carrie witnesses Vampire bursting into her house and flees, but can't escape from him. He grabs her and flies away.
Dr. Davenport and the others discover Carrie is missing and use Wolfmon to find her. Vampire tries to use his powers on Carrie to hypnotize her, but is suddenly turned small again. They realize they need to go back to the drive-in to get big again from hearing the scream. He gets the dog from earlier to watch over Carrie to make sure she doesn't escape.
The good monsters make their way to Carrie and the dog attacks them. It grabs Mummy and Carrie saves him. Big Ed throws some tires at the dog and scares it off. Carrie knows where Vampire went, so they head to the drive-in. The man at the drive-in tells Carrie that the evil monsters attacked him and tried to take "The Shriek," but the guy had sent it back to Raye-Faye (the actress from the film). They head over to Burbank to find her.
Meanwhile, Raye-Faye is flattered that Vampire, Medusa, and Swamp Beast want her autograph, but they just want the film. Vampire tries to scare her so she'd scream, but it fails. Medusa convinces Raye-Faye to let them see the movie again, and she's just about to turn it on until Carrie arrives. The monsters battle each other -- Dr. Davenport and Mummy battle Vampire, Wolfmon fights Medusa, and Big Ed tangles with Swamp Beast. Carrie accidentally turns the film on, and the scream turns the monsters large and they immediately defeat the good monsters.
Raye-Faye grabs Carrie to flee, but the dog under Vampire's spell awaits outside. Carrie tricks it into believing she's Vampire, but the real Vampire also tries to control the dog, confusing it. Medusa gets frustrated and turns it to stone, while Dr. Davenport reverses the film and the reversed scream shrinks the evil monsters, who flee.
Dr. Davenport thanks Raye-Faye and apologizes to Carrie for not accepting her help earlier. Back at Carrie's house, Dr. Davenport tries another experiment, which blows up again. Carrie laughs at this, causing the monsters to grow. They realize Carrie's laugh makes them big, and plan on working together to get rid of Vampire.