Scooby-Doo and the Alien Invaders four Scooby-Doo direct-to-video films to be animated overseas by Japanese animation studio Mook Animation. It was the last film to feature Mary Kay Bergman as the voice of Daphne before her death in November 1999 and the film was dedicated to her memory. The Mystery Machine is driving through a desert in Roswell, New Mexico. A sandstorm comes up and Shaggy Rogers makes a wrong turn onto government property. Seeing a UFO causes Shaggy to lose control of the vehicle and the gang find themselves on the outskirts of a small town. While Scooby-Doo and Shaggy stay with the van,
Shaggy & Scooby-Doo Get a Clue! form, to a high-tech transforming vehicle. However, it usually transforms into machines inappropriate for the tasks at hand (however, in episode 11, it does transform into vehicles appropriate to finish the Polar Bear 3000). In their spare time, Shaggy and Scooby are fans of the show "Chefs of Steel", and the famous mystery solver Chad Chaddington. This is the first Scooby-Doo animated series since 1991 to make extensive use of the Castle Thunder sound effect, which Hanna-Barbera began to stop using around 1994, and was very rarely used on "What's New, Scooby-Doo?" and on none of the post-2003 direct-to-video Scooby-Doo