Morbidia drops the Chest of Demons on the ground and it oddly opens by itself. Even more oddly, the demon captured in the last episode does not escape while the Chest is sitting on the ground open.
The letters on the train that speeds past Scrappy, Daphne, and Flim Flam are HBRR. These letters clearly stand for Hanna Barbera, the production company that produces this show. Also, the founders of the company, William Hanna and Joseph Barbera, are both executive producers of the show.
Vincent VanGhoul: (after the demons are defeated as the sun rises) And now it is the time of light, say farewell to the night. Happily we greet the sun, bringer of laughter, joy, and fun.
(Scooby falls on top of Vincent VanGhoul.)
Vincent VanGhoul: Somebody is getting awfully heavy.
Shaggy: Yeah Scoob, looks like you better cut down on those Scooby Snax.
Scrappy: But if you couldn't get out, how did your shadow do it?
Byron Befuddle: He can pass through walls. When I try it, I hurt myself.
Daphne: Are you sure you know where we're going?
Flim Flam: Pos-olutely.
Daphne: (a bit later) Yeah, we're pos-olutely lost!
Shaggy: Like, abs-itively.
Flim Flam: I once had a third cousin who had a brother who owned a parakeet, and that parakeet's former owner was a lawyer. I can talk us out of this.
Scrappy: This old mine is loaded with ectoplasm.
Flim Flam: And that's what ghosts are made of.
Shaggy: Like I always thought that ghosts were made out of nothing.
Vincent VanGhoul: (opening monologue) As darkness falls and creatures of night howl and shout, the wind in silent whispers warns, that trouble soon will be about.
Scooby and Shaggy: (singing) Me, and my Shadow Demon, strolling down the Graveyard Lane. Me, and my Shadow Demon, looking for a way to raise chain. And when it's twelve o'clock, we'll start to dream, we'll tap and knock, 'til we make you scream. Just me, and my Shadow Demon, everyone thinks we're insane!
The song "Me and My Shadow Demon," performed by Shaggy (Casey Kasem) and Scooby (Don Messick) during this episode, appears on the album Scooby Doo's Snack Tracks: The Ultimate Collection, along with the opening theme from this series.