Season 2 of The New Scooby-Doo Movies reached its pentultimate episode with a guest appearance by singer Mama Cass Elliott, formerly of the Mamas & the Papas. Like other celebrities, Mama Cass was placed as a business owner on this show. In this case, she could've been forgiven for being like a kid in a candy store, since she owned "The Haunted Candy Factory".
Sadly, this was one of Ms. Elliott's last performances, and she didn't sing on this show. Mama Cass passed away not long after this show first aired, if memory serves me correctly.