Scooby-Doo is a long-running American animated television series produced for Saturday morning television in several different versions from 1969 to the present. The series was created by Joe Ruby and Ken Spears for Hanna-Barbera Productions, who produced numerous spin-offs and related works until being absorbed in 1997 into Warner Bros., which has handled production since then. Though the format of the show and the cast (and ages) of characters have varied significantly over the years, the most familiar versions of the show feature a talking Great Dane named Scooby-Doo and four teenagers: Fred "Freddie" Jones, Daphne Blake, Velma Dinkley, and Norville "Shaggy" Rogers. These five characters (officially referred to collectively as "Mystery, Inc.", but never referred to as such in the original series) drive around the world in a van called the "Mystery Machine," and solve mysteries typically involving tales of ghosts and other supernatural forces. At the end of each episode, the supernatural forces turn out to have a rational explanation (usually a criminal of some sort trying to scare people away so that they can commit crimes).