Animation legend Ken Spears, best known as the co-creator of the long-running Scooby-Doo franchise, passed away at age 82 on November 9, Variety reports. Spears’s son Kevin explained that his father died from complications stemming from Lewy Body Dementia (LBD), according to Variety.

Spears started his career in the Hanna-Barbera post-production department alongside former Disney employee Joe Ruby. Scooby-Doo was the duo’s first foray into television development. In an interview with DVD Verdict writer Michael Stailey, Spears told the show’s unlikely origin story. It reportedly began with a meeting he and Ruby had with Joseph Barbera to discuss story ideas for the Wacky Races spin-off The Perils of Penelope Pitstop. Barbera’s agent Sy Fischer stopped them in the hallway afterwards to ask them if Barbera had mentioned CBS executive Fred Silverman’s latest idea to them. Silverman wanted to do an animated program inspired by the classic radio show I Love a Mystery where a group of friends solved mysteries, and was additionally looking for comical teenage protagonists in the mold of The Archie Show. Ruby remembered that Silverman also had a fondness for dogs, so Barbera okayed Ruby’s suggestion to add a dog to the team. Spears and Ruby eventually came up with the character of Scooby-Doo, a lovable Great Dane whose dependability in the face of danger masked immense cowardice, traits they reportedly borrowed from vaudevillian Bob Hope’s comic persona, according to The Washington Post.

Many of the original twenty-five episodes of Scooby-Doo, Where Are You! bear the handiwork of Ruby and Spears. Spears told Stailey that his biggest anxiety at the time had to do with competition from rival network ABC: “We had a lot of fun writing the shows, and the only thing that made us nervous was that we found out that it was going to go up against The Hardy Boys… which was a mystery show as well.” The show wound up becoming such a hit that, as Spears recalled, when Silverman eventually left CBS for ABC in the 1970’s, he bought the rights to Scooby-Doo and immediately ordered forty more episodes for the network. Ruby and Spears were even brought on as supervising producers for a time. Later on in the decade, the two men founded the animation production company Ruby-Spears. The studio was behind a host of Saturday morning cartoons in the 1980’s, such as Mister T, Thundarr the Barbarian and Saturday Supercade. Ruby passed away in August, according to The Hollywood Reporter.

Spears told Stailey that, while he never could have predicted the longevity of the Scooby-Doo franchise, he was grateful that it was such a large part of his creative legacy: “Scooby was one of those once-in-a-lifetime things… It turned out great and you love the show, you love working on the show and so forth, and here we are… Scooby is still as strong as ever.” Stailey’s 2016 Ruby-Spears interview can be heard in its entirety below.

The original two-season run of Scooby-Doo, Where Are You! is available to stream through HBO Max.