Cass Elliot guest-starred on The Haunted Candy Factory episode of Scooby Doo, which aired in 1973. Now, Warner Brothers home entertainment is releasing the episode as part of The New Scooby Doo Movies: The (Almost) Complete Collection and The Best of the New Scooby-Doo Movies: The Lost Episodes,  available June 4!

Read more here: https://www.animationmagazine.net/home-entertainment/new-scooby-doo-movies-come-home-in-almost-complete-lost-episode-sets/