Continuity mistake: When Giles walks up to Buffy, Xander and Willow after The Body is found at the beginning of the episodes, watch the extras walking by in the background. They don't always match as the shot cuts back and forth between Giles and Buffy/Xander/Willow. Ex. When Buffy asks "Vampire?" nobody is walking behind her, but when it cuts to the opposite angle, suddenly two students are walking by from Buffy's direction that weren't there before. This sort of thing happens at least two or three times.
Continuity mistake: After the credits, when Buffy, Xander and Willow sit down to talk about what to do for the talent show, two people walk into the background behind Buffy and are standing there talking throughout the scene. At one point, it cuts to Xander for about one second when he says the line "Whatever happened to corporal punishment?", then cuts back to Buffy, and the two people behind her are suddenly gone. There's not enough time for them to have walked away between shots - they simply vanish.
Continuity mistake: When Snyder grabs Buffy after she breaks into the locker, when she turns around, he is holding her hand up by the wrist. The height he is holding her hand up changes a few times between shots. Sometimes it's up by her face, other times it's level with her neck, at one point it's down by her shoulder, etc. Obviously snippets of a few different takes were used, and he wasn't holding it up at exactly the same height each time.
Nightmares - S1-E10
Continuity mistake: In the season 1 episode "Nightmares", Buffy is talking to Willow about her mom's divorce and she shuts her locker. A few seconds later she shuts her locker again. (00:02:55)
Nightmares - S1-E10
Continuity mistake: In the scene where we see Buffy's mum drop her off at school, when Buffy is worrying that her dad will not show up, we firstly see Joyce's seatbelt is on. We then see her again and it is still on. However after the shot goes back from Buffy to herself, we can see her seatbelt is off. Then when the shot comes back to her again it is back on.
Nightmares - S1-E10
Continuity mistake: When Willow goes down the stairs to the basement, as she reaches the bottom, she goes from looking forward to looking to her right between cuts.
Nightmares - S1-E10
Continuity mistake: When the Scoobies go to talk to Wendall about the spiders, when Wendall says "I don't know what to say about that " he instantly goes from looking forward to looking down between edits.
Nightmares - S1-E10
Continuity mistake: When Buffy's mom first wakes her up after her nightmare at the beginning of the episode, the positions of Buffy's hands, her mother's hand and the bed comforter all change between edits as it cuts from a closeup to a wide shot.
Nightmares - S1-E10
Continuity mistake: When Buffy goes to find Giles, who is going through newspapers, she asks him if he's found anything and he says "I don't know." Between shots Buffy goes from looking at him to glancing downwards with her eyes and then looking back up again between cuts.
Nightmares - S1-E10
Continuity mistake: When Xander, Willow and Giles go out front after Xander punches out the clown, when it changes angles as Willow says "What do we do?!", Xander goes from facing away from to facing towards Giles instantly between cuts.
Nightmares - S1-E10
Continuity mistake: During her "duet", at one point, Willow goes from facing the crowd to facing the other singer instantly between cuts.
Nightmares - S1-E10
Continuity mistake: When Willow is pushed onto the stage, the other singer goes from facing her and gesturing towards her with his hand, to facing forward with his hand down by his side instantly between cuts.
Nightmares - S1-E10
Continuity mistake: When the Scooby gang splits up and Xander walks into the decrepit hallway with debris on the floor and swastikas painted on the walls, he closes the door behind him, but a few shots later, it's suddenly wide open again.
Nightmares - S1-E10
Continuity mistake: When Buffy is confronted by the monster in the school gym, after Billy flees, the monster hits Buffy, and she falls on her back, and her legs both fly up in the air. It cuts to another angle, and her legs are no longer in the air.
Nightmares - S1-E10
Continuity mistake: When Buffy is taking the test in history class, in a wideshot, her teacher walks past her and his shadow passes over her as he walks by. It then cuts to a closeup, and we see his shadow quickly pass over her a second time.
Nightmares - S1-E10
Continuity mistake: When Buffy goes to take her history test near the beginning of the episode and is talking to Cordelia outside the door about how she doesn't think she can pass, pay attention. As it cuts back and forth from Buffy to Cordelia, you see the same student (an African American girl with a black jacket, white shirt and earrings) enter the history classroom twice.
Nightmares - S1-E10
Continuity mistake: At the beginning, when Joyce drops off Buffy at school, pay attention to the car windows. They open and close repeatedly throughout the scene depending on the angle. (This seems to be for the benefit of the scene depending on the camera angle. They seem to lower the window the camera is shooting through while closing the one on the opposite side, and it switches back and forth. Still, it's a mistake).
Nightmares - S1-E10
Continuity mistake: At the beginning, when Joyce drops off Buffy at school, Joyce lets go of the steering wheel and lowers her arms. It then cuts to the opposite angle and Joyce is suddenly holding the steering wheel again.
Nightmares - S1-E10
Continuity mistake: At the beginning of the episode, when we first see Cordelia, she's looking in a hand-mirror and makes a snotty remark to another student. Instantly between the second and third shots she goes from holding the mirror with hand to both hands.
Nightmares - S1-E10
Continuity mistake: At the beginning of the episode when Buffy and Willow stop at Buffy's locker, in the first shot, Willow has her backpack strap on her shoulder and takes it off. It then cuts to another angle and Willow's backpack strap is back on her shoulder, and she takes it off a second time.
Chosen answer: He had larangitis and because of the shooting specifications they had to have him shoot the scene with a bad throat, they then re-recorded his lines and dubbed them. At various points during the scene and indeed the episode you can see him touch his throat or rub it.