Supernatural co-showrunner Andrew Dabb tells Entertainment Weekly that this crossover, despite being animated, is bringing Scooby gang into the Supernatural world and not the other way around.
"It's going to be an episode of Supernatural with Scooby-Doo in it," Dabb said. "It's not going to be an episode of Scooby-Doo with the guys in it.:
Co-showrunner Robert Singer adds, "It's more adult than your average episode of Scooby-Doo. Scooby is the marquee this year. The script really works. It's just going to be great."
Dabb recalls that doing a fully-animated episode of Supernatural is an idea that had been tossed around the writers' room for some time.
"We have ideas floating around sometimes for years before we use them, and that's the benefit of being on a long-running show."
However, doing animation is complicated, and so the idea was always put off. It wasn't until Dabb got a call from Jeremy Adams at Warner Bros. that the idea to turn the episode into Scooby-Doo crossover began to take shape.
"He was like, 'Why haven't they done a crossover with Scooby-Doo?'" Dabb says. "That is an excellent question."
Supernatural getting an early renewal for its thirteenth season meant that the team actually had time to put the animated episode into production.
"The script was finalized and the guys recorded their parts I believe in March of this year and it will air probably about March of next year," Dabb says.
While fans are sure to be pleased with the upcoming Scooby-Doo crossover, many are still wanting to see the Winchester boys interact with a fellow The CW television series, Arrow. One fan even made a pretty stellar poster for such an event. For his part, Arrow star Stephen Amell doesn't think a full crossover will ever happen, but he'd really like to have a cameo.
Supernatural airs Thursdays at 8 p.m. ET on The CW.