In the late 1990s, Paramount Parks-owned Canada's Wonderland teamed up with Sally Corporation to develop Scooby-Doo's Haunted Mansion. The ride opened on May 7, 2000. In November that year, the ride was recognized as the Best New Children's Ride. Paramount Parks then installed the ride at three other locations over the coming four years.
In 2002, Six Flags installed the ride at Six Flags Fiesta Texas and Six Flags St. Louis, with the latter using an existing water ride system. In 2005, Parque Warner Madrid installed the ride (at the time the ride was in the planning stages, the park was operated by Six Flags).ETF Ride Systems manufactured the trackless ride system used on the Parque Warner Madrid installation.
During the 2014 summer season, Six Flags St. Louis had put up a sign in front of their attraction stating, "Scooby-Doo: Mystery of the Scary Swamp will close permanently, September 14, 2014 for future improvements".
This section requires expansion with: more precise details of the ride experience along with appropriate sources. (November 2012)
The ride is a dark ride experience for families which involves shooting laser guns at ghosts and ghouls. Riders in consecutive Mystery Machine-themed cars compete with each other to see who can shoot the most ghosts. The Scooby-Doo theme was licensed from Hanna-Barbera by the ride's creators, Sally Corporation.
The installation at Six Flags St. Louis differs from the rest as it relies upon a water ride system. It is therefore themed to a journey through a swamp. It features different monsters from the Scooby-Doo series as well as the Mystery Inc. gang popping out of trees and shrubs.
The outsides of the show buildings are decorated with a fiberglass blue and purple castle with stylized turrets. Two circular windows resemble eyes while the entrance to the castle resembles a mouth. Guests entered the attraction by passing under a Gothic-style arch bearing the rides name, and that was adorned on either side by the letters "GM," standing for Ghastly Manor.