A Night of Fright is No Delight - S1-E16
Continuity mistake: When Scooby, Shaggy and Velma go up the elevator, Velma operates it with a hand lever, but when they arrive at Cousin Slicker's room, the lever has gone.
A Night of Fright is No Delight - S1-E16
Continuity mistake: When the gang meet up and realise that all the heirs are missing, Daphne is behind Scooby, but in a close-up of Scooby in the next shot, she has disappeared.
Continuity mistake: When the villain drops the wall flat on Shaggy, it drops with Shaggy going through the window as he stands, then hits the floor. The next shot the flat on the floor disappears, then reappears in the shot after that.
Continuity mistake: When Scooby dons the cloak and hat, there is a blank wall behind him. As he begins running, Shaggy is suddenly with Scooby and a shelf filled with boxes appears on the previously blank wall.
Continuity mistake: A wall flat behind Shaggy with an open window and a closed door is pushed by the villain to fall onto Shaggy, but door on the flat disappears and is now an open space in the wall flat.
A Gaggle of Galloping Ghosts - S1-E11
Continuity mistake: The Frankenstein monster suddenly appears outside the pantry door after Scooby opens the door - the monster did not walk out, but just appeared.
Continuity mistake: Velma has her arms spread as she stands in front of the Scooby gang, but nobody is behind her in the next shot.
Continuity mistake: Velma counts off the clues on her fingers close to her face, but in the next shot her hands are at her side.
Continuity mistake: Velma is facing to her right as she holds the engraving plate, but the next shot she is facing left.
Continuity mistake: Shaggy's hands on the violin case change positions depending on whether the case is open or closed.
A Gaggle of Galloping Ghosts - S1-E11
Continuity mistake: In the Mystery Machine, Daphne is seated close to Fred, but the next shot shows her alone.
Continuity mistake: After the villain is caught, Scooby is in the theater rafters, but his spots are missing.
Continuity mistake: The background houses and fences repeat as Shaggy and Scooby carry their pizza home.
Continuity mistake: While Scooby and the gang speak with the doorman, Scooby's spots disappear.
Bedlam in the Big Top - S1-E10
Continuity mistake: The opening scene shows the clown overlooking the circus tent from a clear bluff, but the closeups show the clown hiding behind bushes.
Bedlam in the Big Top - S1-E10
Continuity mistake: Max the Midget rides Scooby into the middle of the Mystery gang, but the next shot shows Max and Scooby standing apart from the gang.
Bedlam in the Big Top - S1-E10
Continuity mistake: After meeting Mr. Barnstorm, Fred is driving the Mystery Machine from the passenger side, but the next shot from the front view shows Fred driving from the left (driver's) side.
Bedlam in the Big Top - S1-E10
Continuity mistake: Mr. Barnstorm is close in with the gang looking at the ghost clown in the cage, but the next shot shows Mr. Barnstorm alone.
Bedlam in the Big Top - S1-E10
Revealing mistake: The clown's left leg goes through the solid wood floor of the wagon as he flies into it.
Bedlam in the Big Top - S1-E10
Continuity mistake: The baggage on the back of Samson's tandem bike change colors as the scene plays out.
Chosen answer: A ghost wouldn't have to keep any food in the fridge - they don't need to eat. So it is one thing that proves the ghost is not a ghost.