This is the fourth episode Bogel and Weerd aren't in despite the fact it was their goal to contact each monster released from the Chest of Demons.
The Scooby Doo, Where Are You! (1969) title card appears in this episode (thus breaking the fourth wall in the process).
Clips from "When You Witch Upon a Star" were used in a fundamentalist Christian documentary titled Deception of a Generation (1984), which heavily profiled and criticized the series for exposing children to the occult.