A mysterious creature dubbed the Sludge Monster robs a local bank. When the "monster" appears in Scooby's doghouse, the kids chase it through an underground sewer tunnel--and into the office of the bank president!
A "cheese monster" frightens away all the workers at the Scooby Snack factory, so no more Scooby Snacks can be made. But without a Scooby Snack, Scooby won't pursue the monster. The kids convince Scooby to help unmask the bad guy and reopen the factory.
At the Comic Book Convention, the monstrous Dr. Croaker pilfers Shaggy's valuable collector's edition of "Commander Cool." Shaggy and Scooby don superhero outfits to investigate the bad guy who's stealing valuable comic books.
Shaggy and Scooby compete on a TV game show--until the ghost of notorious gangster Al Cabone disrupts the program. The ghost tries to locate his secret treasure vaults hidden somewhere inside the television station, and his presence convinces the owner to sell the property. The kids follow clues and eventually unmask the ghostly culprit.
When Shaggy leaves his little sister with a babysitter, the sitter absconds with the child. Meanwhile, a movie monster prowls nearby and an escaped convict attempts to locate his buried loot. The kids have a wild time sorting out the mess.
On a ski vacation in the mountains, the gang encounters all sorts of problems: no snow, an ice demon, an abandoned gold mine, and a greedy developer who offers to buy the land their chalet sits on for very little money. The kids sort through an avalanche of clues as they work to solve the mystery.
The authorities mistakenly suspect that Shaggy and Scooby stole two valuable Samurai swords from a museum. But the two friends saw the actual thief--the ghost of an evil Samurai! To clear themselves, Scooby and Shaggy must solve the mystery of the missing swords.
Velma's Aunt Thelma summons the Scooby-Doo Detective Agency. She's head of the Marine Institute, and their dolphins are disappearing. The scary Headless Skateboarder and the frightening Seaweed Monster are just two of the culprits the gang pursues as they unravel the mystery.
A sweet little ghost has lived peacefully with a kind old couple for years, when suddenly a nasty pirate ghost arrives and demands that they all vacate the premises. The nice ghost asks Scooby and his friends to learn who the mean ghost really is and what he actually wants.
On an Indian reservation, Scooby and the gang confront a Totem Pole Monster who orders them off his land. According to Indian legend, the Totem Spirit appears when sacred Indian land is threatened. The kids soon discover that developers want to build a hotel on the site where the Chief's home stands. Finally, the gang unmasks the real person behind the mystery of the Totem Pole Monster.
After a thief breaks into Daphne's room, Scooby discovers that he's got competition in the detective dog division--Robopup, a mechanical wonder dog. While Scooby attempts to compete with the technological marvel, the gang solves the mystery.