The Grim Adventures of Billy and Mandy (2001)

Season 3: Episode 12

When Billy, Mandy and Grim go playing golf, they encounter boy wizard Nigel Planter again, who is there hiding from the dark wizard Lord Moldybutt. They head back to the School of Sorcery, where they keep on running into Moldybutt, who warns them to stay away from the "Chamber Pot of Secrets" hidden in Dean Toadblatt's office. It is revealed that Lord Moldybutt is actually Toadblatt, who was disguising himself to scare off Planter. Note: The title is a spoof of Harry Potter and the Chamber of Secrets.