Don't Fool With a Phantom - S2-E8
Other mistake: When the wax phantom appears behind Scooby and Shaggy the man who supposedly is impersonating him in the suit is in clear sight directly behind Fred Daphne and Velma.
Continuity mistake: The Snow Ghost's mask goes from being a hood type to just covering the guy's face in one shot when he's stuck in the snow.
Mine Your Own Business - S1-E4
Other mistake: When Daphne falls down the mine shaft, Fred has turned his head around his body 180°.
Scooby's Night With a Frozen Fright - S2-E4
Continuity mistake: Prof Ingestrom's parka is found, then it becomes Prof Wayne's parka.
Scooby's Night With a Frozen Fright - S2-E4
Continuity mistake: A heater on a table disappears then reappears as the gang investigates the room.
What a Night for a Knight - S1-E1
Plot hole: It seems unlikely that: 1. The curator, who's short and chubby could fit into that suit of armor. 2. How he could be strong enough to lift up the table Scooby and Shaggy are hiding under at one point, 3. That the museum has no security guards who might catch the curator and his thugs during their art forgery scheme and 4. There are eyes shown moving in the suit of armor when the gang's talking to the curator despite the fact he's the Black Knight Ghost.
What a Night for a Knight - S1-E1
Continuity mistake: Scooby's carrying the left shoe of the missing Professor White yet when they find him he's missing his right shoe.
Audio problem: Velma's voice comes out of Daphne's mouth at one point when they're scuba diving.
Continuity mistake: Shaggy's hair is briefly blond when the gang's scuba diving.
Scooby-Doo and a Mummy Too! - S1-E12
Plot hole: If the guilty man knew the diamond scarab was in the hippo statue then there's no reason he couldn't have broken the statue open and taken it.
Bedlam in the Big Top - S1-E10
Continuity mistake: The Ghost Clown's lips briefly turn light blue when he's hypnotizing Daphne.
Continuity mistake: The director's shown being outside the trailer in one shot after having been in the trailer before and after this shot when they're looking for the missing stuntman.
Continuity mistake: Carl, the stuntman, is shown barehanded in his trailer's trunk in one shot. When he says he's quitting he's suddenly got on ape gloves.
A Tiki Scare is No Fair - S2-E6
Continuity mistake: The Witch Doctor seems to be wearing just his robe and mask. When he's unmasked as Mr Simms suddenly we can see hints of his suit jacket sleeves sticking out.
A Tiki Scare is No Fair - S2-E6
Continuity mistake: When the witch doctor's caught by the statue his arms are free. Just before they unmask him suddenly they're trapped at his sides. When he responds to Fred his arms are free again.
Continuity mistake: When Mr. Fong and his henchman are arrested at the end of the episode, you can see Mr. Fong's Zen Tuo costume is white, but later on in the scene, it turns black.
Continuity mistake: During the chase scene, we see the Fisherman's Wharf sign and then cut to the Mystery Machine turning around a corner. At this point, you can see Scooby is in the vehicle with the rest of the gang, but just a few seconds later he is back on top of the Zombies' car.
Continuity mistake: When Scooby slides out of the Mystery Machine during the chase scene, he stops at a pier and you can see there is a brick wall behind him, but when we see Scooby in the next shot, the wall has disappeared.
Mine Your Own Business - S1-E4
Continuity mistake: When Fred says that "I have a hunch that he'll turn up soon", there is a tape recorder on the desk and Daphne and Fred are standing in front of it, but in a close-up of the recorder, Daphne and Fred have gone.
Mine Your Own Business - S1-E4
Continuity mistake: When Scooby and Shaggy are standing at the closet doors, the door where is Shaggy is standing has the knob on the right hand side, but when the two swap places, Scooby opens the door and the knob is on the left hand side.
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.