Plot hole: Given he fell down into a ravine it seems impossible for Carl to have got back to his trailer before Mystery Inc does.
Bedlam in the Big Top - S1-E10
Continuity mistake: Velma throws the umbrella to Scooby pointed end first, but when it arrives at Scooby, the umbrella is handle-end first.
Bedlam in the Big Top - S1-E10
Continuity mistake: After the umbrella turns inside out, Scooby loses his grip with the umbrella and falls to the trampoline, but the umbrella does not follow Scooby down.
Bedlam in the Big Top - S1-E10
Continuity mistake: The table behind Shaggy changes color several times as he performs the Lion Tamer act in the cage with the lion.
What a Night for a Knight - S1-E1
Continuity mistake: When Velma loses her glasses, the Black Knight trips over her and lands on the guillotine. She mistakes the Black Knight's growls for Shaggy's sore throat, and pours some cough mixture on to a spoon. When Shaggy enters and runs up to Velma, she is wearing her glasses again.
What a Night for a Knight - S1-E1
Continuity mistake: When Velma says "What a spooky place!" to Scooby, you can see Velma is standing by Scooby but in the next shot she has disappeared.
What a Night for a Knight - S1-E1
Continuity mistake: When Scooby is guarding the door, it is open. When he stops, it is open, and in the shot after that, the door is closed again.
What a Night for a Knight - S1-E1
Continuity mistake: When the gang arrive at the Museum, you can see the handle on the Rear Entrance door is on the left hand side. When Shaggy opens the door and lets Fred, Daphne and Velma in, the handle is now on the right.
What a Night for a Knight - S1-E1
Continuity mistake: When Shaggy puts the ladder on the wall near the Museum Rear Entrance, you can Fred is standing by an open door of the Mystery Machine. In the next shot, he is now standing near Shaggy.
What a Night for a Knight - S1-E1
Continuity mistake: When the gang say "Professor Hyde White!" in the library, you can see Shaggy has his hand on Fred's shoulder. When we Fred and Velma in the next shot, he doesn't.
What a Night for a Knight - S1-E1
Continuity mistake: When the gang are driving along in the Mystery Machine, you can see Velma is sitting by the window. When we see a full view of the front seat, she is now sitting between Shaggy and Daphne.
What a Night for a Knight - S1-E1
Continuity mistake: When Mr Wickles is standing by the crate containing the Black Knight armour, you can see the lid is resting on it. But in a close-up of Mr Wickles, the lid is missing.
What a Night for a Knight - S1-E1
Continuity mistake: When the gang discover an empty suit of Black Knight armour in the truck, you can see the helmet is beside the wheel. When Daphne notices a piece of paper by the wheel, the helmet is nowhere to be seen.
What a Night for a Knight - S1-E1
Continuity mistake: When we see the truck at the beginning of the episode, you can see that the label on the crate is completely clear. When the Black Knight opens the crate, the label now has writing on it.
Don't Fool With a Phantom - S2-E8
Continuity mistake: When Fred says "Are we glad to see you guys!" after grabbing hold of Shaggy and Scooby, you can see behind Velma there is a hole in the wall. But in the close-up of Velma in the next shot, the hole has gone.
Don't Fool With a Phantom - S2-E8
Continuity mistake: When Shaggy and Scooby Doo are on the floor after escaping from the Phantom on the conveyer belt, you can see there is some rope around them. But when the two run away from the Phantom, the rope has gone.
Don't Fool With a Phantom - S2-E8
Continuity mistake: When Shaggy and Scooby Doo arrive at the dinner table, you can see there is a jelly opposite the chicken. But when the Wax Monster comes to the table, the jelly has gone.
Don't Fool With a Phantom - S2-E8
Continuity mistake: At the museum, Fred discovers a sign saying "Wax Phantom Display" on a concrete block. But when we see a full view of the gang a few seconds later, the sign and the block have disappeared.
Don't Fool With a Phantom - S2-E8
Continuity mistake: Daphne is wearing pink tights at the start of the episode, but when the gang discover that the safe was robbed after freeing Johnny Sands, look at Daphne and you can see her tights are missing. They reappear when we see her with the gang a little later on.
Don't Fool With a Phantom - S2-E8
Continuity mistake: In one shot of Fred, Daphne and Velma at the TV station, you can see there are some lights behind Daphne, but when we see a close-up of her, the lights have gone.
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.