Even though hypnosis can turn Shaggy and Scooby evil, it cannot eliminate their goofy, over-the-top personalities.
The use of an antagonist purporting to be "Black Knight", brought from England to America, harkens back to the first-ever-aired Scooby Doo production, What a Night for a Knight (1969).
The following snippets from this episode can be seen in the opening sequence for The Scooby-Doo Show.
- Shaggy holding Scooby after the two are frightened (again) by the ghost knights, albeit set on a dark or blue background depending on the version of the sequence being viewed.
- Merlin appearing and waving his wand, again set on a dark or blue background depending on the version.
- Shaggy and Scooby gulping after being told the gang are going into the castle, yet again set on a dark or blue background depending on the version.
Uncle Shagworthy is one of many incredibly wealthy relatives of Shaggy, a hippy who travels around the country in a van.