Old Man Smithers was a janitor working at the Wow-O Toy Factory and had a crush on the factory's owner Pamela Anderson and decided to ask her out to which she turned him down. Furious over her rejection Smithers decided to dress up as the Luna Ghost and haunt the factory out of business as a method of vengeance. When Mystery Incorporated appears on the case they come up with a plan to trap the ghost only for the latter to kidnap Daphne, the plan is still set into motion however before Scooby and Shaggy accidentally mess it up after being mortified at the sight of the ghost. Fred ends up attempting to spray the ghost with a hose but unintentionally hits Velma instead knocking her over a balcony and coiling a chain around her leg, Fred himself then has a large net fall on top of him. The Luna Ghost continues to hold Daphne and chase Shaggy and Scooby before the two knock him into a large pile of packaged dolls rendering him unconscious.
Pamela, fans of Mystery Inc, the press and authorities appear on the scene and thank Mystery Incorporated for their hard work and the Luna Ghost is then unmasked as Old Man Smithers who haunted the factory after Pamela has divorced him.
He also made a cameo in Scooby-Doo! Mystery Incorporated as one of the costumes in the museum. The Slime Mutant is the next villain after all the villains like the Luna Ghost
Old Man Smithers has a taste for theatricality, choosing to commit his crimes in a glowing white suit and intimidate his victims with pyrotechnic tricks. He shows a sadistic side while disguised, as shown by him scorching Scooby's tail and scaring Shaggy.
He has a fixation on younger women, as shown by him trying to get revenge on Pamela Anderson for turning him down and kidnapping Daphne. He is single-minded, not considering or caring that haunting his place of employment could be harmful to him.
Luna Ghost unmasked
The Luna Ghost as featured on the poster for the movie.
Despite having very minimal screen time, the Luna Ghost quickly became a fan favourite and is one of the most highly praised parts of the 2002 Scooby-Doo movie.
Although he was only the opening antagonist of the feature, he was used in a vast majority of the marketing for the film and his silhouette preparing to attack the gang is present on nearly all of the home media releases and posters. This is likely because in most of the original drafts of the movie the Luna Ghost was supposed to be the main antagonist as opposed to Scrappy Doo and N' Goo Tuana.