[2] The Mystery Inc. gang are in a covert operation in Elvira's Halloween of Horrors Parade in Crystal Cove to capture the Haunted Scarecrow.

Before being pulled away by the federal agents, Dr. Crane tells Velma that his drones did not leak, thereby giving a hint that she missed something in her reasoning.

On the way, they come across a stray disabled drone in a pumpkin patch with "Tot Alli Frame" engraved on it and a truck full of toxic waste.

The pumpkins coming in contact with the mixture of toxic waste and Dr. Crane's fear formula turn to animated monsters.

They quickly return to town and interrupt an ongoing interview of the other Mystery Inc. gang members to inform them about the 'Jackal Lanterns' of the pumpkin patch.

The Mystery Inc. gang comes together with Elvira, Mike, and Michelle and eats Scooby-Snacks to enter Velma's mind palace, an imaginary plane where they recount the night's events.

During the credits, the gang (including Bill Nye) helps Fred rebuild the Mystery Machine from what happened earlier in the film.

[3] It was directed by Maxwell Atoms (and therefore includes a style of humor similar to that of The Grim Adventures of Billy & Mandy) with Sam Register as producer.