When the gang return the knight to Mr. Wickles, the knight's eyes can be seen during the converstation. However, Mr. Wickles is later revealed as the villian. So he shouldn't be around when the knight was alive.
When Velma says "So that's where the old knight was headed for", her lips don't move.
Velma mentions that Shaggy was a gymnast in high school.
When Daphne picks the back door in the hidden room, the knight comes out. The knight's suit of armor was missing its helmet design, but in the next scene, it's back on again.
When Scooby puts on the suit of armor at the end of the episode, the suit was fitted perfectly for Scooby's paws, even though earlier, it was made for fingers...not paws.
We learn in this episode that Shaggy is a ventriloquist.
After Shaggy falls from the top window of the museum, he lands in a pile and then gets up and walks away wearing a hat. Then the camera changes and the hat is gone like it just vanished.
Why would a WWI-vintage airplane that's part of a museum exhibit have gasoline in its engine and be in full working order, thus enabling it to fly around the museum?
At which point before administering the cough medicine to Shaggy did Velma find her glasses?
During the scene in which the knight gets trapped in the stockade, Velma, who has just lost her glasses, starts to pour some cough medicine into a measuring spoon to give to the knight, whom she mistakes for Shaggy. The scene then switches to Shaggy who is looking for Velma, and then back to Velma, who is now wearing the lost glasses and is just about to administer the cough medicine.
Shaggy: What a nervous night to be walking home from the movies, Scooby Doo. And all because you had to stay and see "Star: Dog Ranger of the North Woods" twice!
Shaggy: I've seen guys do the splits, but this is ridiculous.
Daphne: Hey look! A secret room!
Shaggy: Somebody sure is a messy housekeeper!
Daphne: Gol-ly. This place sure is creepy at night.
Shaggy: It's even creepy during the day.
Fred: That settles it. There's something fishy going on in that museum.
Scooby: You mean?
Fred: That's right Scooby. Tonight we're going fishing.
Fred: What's an empty old suit of armor doing in the driver's seat of this pick-up?
Shaggy: Maybe he went out for the night.
(Scooby stops suddenly and Shaggy trips over him)
Shaggy: Like next time, signal.
Velma: Will you do it for a Scooby Snack?
Daphne: Let's take this back way out! (Black Knight appears)
Shaggy: Leave it to Daphne to pick the wrong door.
Fred: (referring to mummy case) Come on Shaggy. Help me open it.
Shaggy: Uh uh. Don't like suprises. Especially spooky ones.
The Black Night appears in Scooby Doo Night Of 100
Villian:J. WicklesReason: He and the gang of forgers were stealing paintings and replacing them with fake ones. So, he had to kidnapped Professor Hyde White because he was the only person who could've spotted the fakes.
We see the back door of the Mystery Machine open in this episode, something that doesn't happen very often. It also appears to be stocked with various supplies, like a first aid kit and a ladder. Typically the back of the Mystery Machine is completely empty.
Adapted into the comic book story of the same name (Gold Key issue #1, March 1970).
Professor Hyde-White makes a cameo appearance (one of the many masks pulled off at the unveiling of the culprit) in the 1997 JOHNNY BRAVO episode "Bravo Doobie Doo" which guest stars the entire gang.
For the first few episodes, some translations will also have the end theme in English rather than just music or the song being sung in that language.
This episode isn't shown that often on TV. The rest of the episodes appear a lot more often.
In Scooby-Doo 2: Monsters Unleashed, the Black Knight Ghost plays a large role. Peter Boyle plays the part of Mr. Wiggles.
Velam loses her glasses for the first time.
The main source of inspiration for this came from Enid Blyton's Famous Five books, that involved four youngsters, and their dog, solving crimes and mysteries.