'Scooby-natural' will debut during the CW series' upcoming 13th season.
"I want to do a Scooby-Doo season," he confessed. "Scooby-natural, all 22 episodes."
The "Scooby-natural" episode was announced at the CW's Upfront presentation in May, but there's a few details still up in the air, like which car is faster, between Supernatural's famous Impala or Scooby-Doo's Mystery Machine.
"You'll have to see," Padalecki teased. "Depends on who's driving, I guess."
"It is a charming and very funny episode," Supernatural executive producer Brad Buckner added. "It's like the better meta episodes, where you have fun with what the show is and now you get two shows to tweak. There's a certain amount of expertise on a certain brother about what Scooby world is, and we have fun with that."
Season 13 will also feature the pilot episode of the long-running series' spinoff, Wayward Sisters.
"Its DNA will absolutely be recognizable as 'the child of,' as opposed to an entirely separate-looking thing," Buckner explained of the spinoff series, which centers on Sheriff Jody Mills (Kim Rhodes) as she creates a monster-fighting force out of a group of troubled young women orphaned by supernatural tragedy.
"It'll be borne out of our context," Supernatural EP Eugenie Ross-Leming offered. "I think it will have the flavor of the show with a more estrogen-heavy slant."
Supernatural returns Thursday at 8 p.m. ET/PT on The CW.