Scooby-Doo 3

Scooby-Doo 3 was a planned sequel to Scooby-Doo 2: Monsters Unleashed that was set to be the third installment in the live-action Scooby-Doo film series.

Plot
According to James Gunn:

The Mystery Ink gang are hired by a town in Scotland who complain they’re being plagued by monsters but we discover throughout the film the monsters are actually the victims & Scooby & Shaggy have to come to terms with their own prejudices & narrow belief systems. (Yes, Really!)

Why It Was Cancelled

 * 1) The first two Scooby-Doo films were panned by critics, audiences and fans alike, despite being box office hits.
 * 2) After the second film was released, Matthew Lillard said in an August 2004 interview that there wasn't going to be a third film.
 * 3) Co-creator Joseph Barbera died in December 2006 before he could have a hand in making a third film.
 * 4) Although the first two films were box office hits, Warner Brothers was disappointed with the box office returns of the previous films.

Results

 * The third film was permanently cancelled.
 * There was a made-for-TV film called Scooby Doo! The Mystery Begins with mostly new cast members as the human characters. The rest of the films following The Mystery Begins were released straight to DVD.
 * The film series will be rebooted with a CGI-animated movie from Warner Animation Group titled Scoob!, set to be the first installment of the Hanna-Barbera shared cinematic universe. It was going to be released on May 15, 2020. However, it was delayed indefinitely due to the coronavirus pandemic.

External link

 * Matthew Lillard says "No Scooby Doo 3"