Once More, With Feeling - S6-E7
Continuity mistake: During the final song, everyone, including Spike, sings "When Does the End Appear?", however, one shot later, Spike is seen starting to sing the word "appear" again and then he stops.
Continuity mistake: When Spike is looking out the window at the demons rampaging in the street outside Buffy's house, Dawn can be standing behind him with her hair trailing down below her breasts. In the next shot, when Spike pulls her away from the window, her hair is pulled back behind her shoulders despite her not having moved. (00:53:10)
Continuity mistake: In 'Flooded', Jonathon reads a few things off the board listing the Trio's ultimate aims. One of the things he reads out is "prototype jet-packs that actually fly", but when the list is shown a few seconds later jet packs aren't mentioned on it. (00:27:10)
Continuity mistake: Lily's boyfriend is taken into an alternate dimension, where time moves quicker than ours, and is kept there until he is an old man. But when Buffy finds him, she realizes who he is because of his tattoo - which has not faded or aged in any way. (00:23:20 - 00:34:30)
Continuity mistake: The security tag on Buffy's new jacket shifts when Buffy first sees it. (00:12:50)
Continuity mistake: Buffy's shoes change from being nice shoes, to runners (e.g. When Buffy climbed out of her grave, she had nice shoes, but when she jumped over the fence, she had runners on).
Out Of Mind, Out Of Sight - S1-E11
Continuity mistake: When the gang are in the cafeteria and Giles comes along, Buffy's hands instantly change positions as she says "I love it when he says that!" Then, in the very next shot, a drink suddenly appears in her hand that wasn't there before.
Continuity mistake: In the basement, immediately after Buffy pulls her hand out of the demon's chest, her fist is completely dry. Two shots later, it is covered in gooey demon fluid. (00:40:35)
Continuity mistake: Timothy is wearing disposable gloves as he is training Buffy at the grill, but in the shot when he puts the raw patties on the grill, he is barehanded. (00:16:15)
Continuity mistake: In 'This Year's Girl' when Faith is taunting Joyce with all Buffy's uncollected mail she flings the envelopes across the bed one by one, scattering them. When Faith is fighting Buffy later on they are all in a pile again. (00:37:20 - 00:38:40)
Continuity mistake: In the episode 'Anne' when the latest people to be brought into hell are lined up with a demon talking to them, there are 3 or 4 people standing between Buffy and Lily. When the demon asks them all in turn 'Who are you?' we see him asking Lily and after that the shot rests on Buffy, but in the background we only hear him ask one more person before he gets to Buffy. (00:35:50)
Continuity mistake: In 'The Initiative', Riley, Graham and Forrest are looking in through the windows of Stevenson Hall with thermal goggles looking for Spike, they see him walking towards Willow. When we see Willow and Spike seconds later he is still sitting on the bed where he was for most of the scene. (00:37:30)
Continuity mistake: After the 'hell hogs' interrupt the ritual, Xander pulls Willow out of the way. He then tells Anya and Tara to "take off." which they appear to do, starting to run Into The Woods. But then in the next shot, they are back standing still in the clearing (on the left of the shot).
Continuity mistake: When they ask about the demon that Xander and Cordelia encountered in Buffy's basement, Xander points to the bug that Cordelia threw from her hair onto the open book. He then slams it shut. A shot later, the book is gone.
Continuity mistake: When Buffy wakes up she is wearing metallic nail polish, yet when she went to sleep previously, she has no nail polish on. Later in a scene where Buffy is dreaming about her night with Angel she has the nail polish on again, even though that took place the night before when she did not have her nails painted. (00:01:15)
The Dark Age - S2-E8
Continuity mistake: Cordelia tells the Scoobies that Giles was talking to the police about a homicide, but this wasn't mentioned in the time that she was in the room. (00:18:15)
Seeing Red - S6-E19
Continuity mistake: At the beginning of the episode, Buffy is running from the large saws and jumps out the door, she sits up and you can see the book is fully intact and in one piece. After the opening credits Tara picks up the same book and it falls apart from being cut in half.
Continuity mistake: When Willow catches Xander and Cordelia kissing in the library, the hair next to Willow's right ear moves between shots as her and Xander are talking in the hallway.
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.