Night of the Living Doo is an animated television special that aired on October 31, 2001. The cartoon is a comedic parody of a typical episode of The New ScoobyDoo Movies, complete with unlikely guests and a retro style. The special was produced by Cartoon Network and broadcast in small segments during commercial breaks of a Halloween ScoobyDoo marathon. At the end of the marathon, the complete special was broadcast in its entirety.
Source: Wikipedia