Continuity mistake: When Harry storms into the pub in Hogsmeade, the camera follows his footprints to the door, and at the door is a large clearing where there is no snow, because the ground is sheltered by the door's porch. Yet in the following shot the clearing has decreased greatly. (01:01:35)
Continuity mistake: When Potter is looking at the 'Jack in the box' you can see Lupin in the background flipping his wand forward. When it cuts he has his hand and the wand behind his back. (00:42:10)
Continuity mistake: In the corridor when Harry shows the blank map to Snapes he is holding it only in his left hand. When the view switches he has both hands on it, and in the next shot is again holding it in one hand. (01:13:00)
Continuity mistake: Just before the Knight Bus starts to squeeze between the two double decker's, watch the annoying Shrunken Head at the front of the bus. There's a long shot as the bus is just about to squeeze, and the head turns round to face Harry. There's a shot of Ernie pulling the leaver, then a close up of the head as it turns round again, and says, "Mind your head." (00:11:40)
Continuity mistake: Outside Hagrid's, when Fudge says "We must search the grounds," the way Dumbledore holds his staff changes between shots. (01:50:15)
Continuity mistake: When Marge and the family are eating, Mr. Dursley pours Marge some brandy. She then tells him to pour a bit more, and in one shot he is holding the brandy bottle and glass away from each other, yet in the following shot he's pouring brandy into the glass. (00:02:35)
Continuity mistake: After Harry arrives at the Leaky Cauldron, Tom brings him to meet with Fudge. When Tom leads Harry to the chair in the wide shot, it is at a diagonal, but in the next close-up it faces the table head on. It changes in following shots as well. (This has nothing to do with the shape of the chair's arms.) (00:13:10)
Continuity mistake: When Snape and Harry are in the hallway and Lupin shows up and Snape goes, "Well, well, Lupin," you see Harry in the background attempting to tuck away the Marauder's Map in his pocket. When Snape grabs for it, he reaches up more, as if Harry is holding it more by his shoulder.
Continuity mistake: When Harry climbs out of tunnel into Honeydukes, the boxes on the stairs are straight up against the wall, including the box with the lollypops on the fifth stair. However, in the next shot from above, the box is farther from the wall for the effect. (01:01:00)
Continuity mistake: In Hagrid's hut, Hagrid gets something from a cage, and then he tosses it for his creature to eat. If you look closely, you'll see Hagrid *accidently* throws the item over the creature, nowhere near its mouth, yet in the following closeup the item is still flying towards the creature's mouth, and the creature gobbles it up contently! (01:21:00)
Continuity mistake: When Harry puts his trunk on the pavement and sits down you can see him putting both hands to the ground. When it cuts while he is sitting down, you see him supporting himself on the trunk with his left hand. (00:07:10)
Continuity mistake: When Harry attacks Malfoy, he pulls Crabbe's pants down. When Malfoy and Crabbe start to run up the hill, in one shot, Crabbe's pants are down by his ankles. In the very next shot, his pants are up near his waist and he wouldn't have had time to pull them up between shots. (01:00:30)
Continuity mistake: When Ron drops Scabbers after Buckbeak has been 'executed', he and Hermione are very close together, note the position of their feet. In the next shot, when Ron says, "He bit me," Hermione is now standing farther away from him.
Continuity mistake: After the Weasley's have handed over the Marauder's Map to Potter, George puts his wand on the Map while saying, "I solemnly swear that I'm up to no good." When it cuts to a closeup of the map, you can see the way Potter is holding it changes, and the way George's wand is on it changes. (00:57:25)
Continuity mistake: The angles, length and position of Harry's scar on his forehead, change considerably throughout the film. (02:00:25 - 02:02:05)
Continuity mistake: In the "Care of Magical Creatures" scene, Hermione gets a fright and there is a close up of her grabbing Ron's sleeve. From a different shot seconds later, you can see her grab his sleeve again in the distance.
Continuity mistake: When Harry enters the Leaky Cauldron you see Tom bowing while stretching his left hand out. When it cuts he is holding his left hand behind his back. (00:12:00)
Continuity mistake: As Malfoy is approaching Buckbeak saying, "You great ugly brute," we see Hagrid turn around. Watch the dead ferrets hanging around his neck. They hang further down around his neck than they do in the next shot. (00:35:25)
Continuity mistake: When Malfoy and his friends take off, after Harry has beaten them, you can see Hermione and Ron standing in the background with their backs to a fence. When it cuts to a closeup of them they are suddenly standing behind a tree. (01:00:30)
Continuity mistake: As Vernon watches Marge float away, he is on his knees on the grass in the backyard, with Petunia beside him. Still on his knees as Vernon shouts, "Please!" in the shot from inside, his position on the grass is now centered with the door, so as to be visible for this shot. (00:05:50)
Chosen answer: It's not known what it is. It is left to the audience's imagination of what exactly is in the room or what some witch or wizard was doing in there. This is only meant to be a humorous bit and is unrelated to the plot. It didn't happen in the book.
raywest ★