Continuity mistake: Hyde must have gone into the future to get his Spiderman pillowcase because it has the Spiderman logo from the 1990's on it, not the 1970's one.
Continuity mistake: When Donna introduces Sarah to the gang, she states that it took her 6 months of sorting records to become 'Hot Donna'. In season 3 episode 14 "Radio Daze" Donna has just started working there and gets the name 'Hot Donna' immediately. (00:01:20)
Continuity mistake: When Kitty asks Red for a cat Red is reading a copy of Time magazine. He closes the magazine and puts it down on his knee while he tells her why he doesn't want a cat in the house but in the next shot the magazine is back in his hands and open to where it was before he closed it.
Continuity mistake: When Hyde enters the scene, his shirt is somewhat tucked behind his belt. In the following close-up shot his shirt is above the belt but returns to the tucked position in the next shot. (00:00:10)
Continuity mistake: When Fez knocks the clown over and shatters it, you see the head roll in front of the body and out of frame with the nose still attached. Donna then turns around and runs in to take the nose from behind the body of the clown.
Continuity mistake: When Jackie leaves the basement and Lorie comes down she's wearing green pants, but as soon as she walks away they're blue jeans. The shirt, jacket are the same, but it's the pants that change.
Oh, Baby We Got a Good Thing Goin' - S7-E18
Continuity mistake: When Kelso is trying to get the baby to not cry, you can tell Bob covers its face to the camera so we don't see that it's not actually crying. Cut to a different angle, and the blanket surrounding the baby has moved. Cut back, and the blanket is covering the baby again.
Continuity mistake: In the crowd scenes, Jackie comes back to her seat. A man sitting next to Donna looks at Jackie. The scene changes angles, and the man is looking straight.
Squeezebox - S6-E20
Continuity mistake: Kelso gets really close to Eric when he's trying to burn him about the other girl. The shot changes, and Kelso is further away.
We're Not Gonna Take It - S6-E6
Continuity mistake: When Eric is carrying the tray and they're trying to get him to drop it, he hops over a chair. The tray rotates between cuts. Look at the glasses.
Continuity mistake: The unibrow drawn on Jackie changes between the time we first and last see it. It's thicker the second time.
Garage Sale - S2-E1
Continuity mistake: At the movies, Fez is daydreaming. Jackie's hand comes into frame as she's about to reach into his popcorn bucket. The shot cuts and her hands are at her side. She subsequently repeats the action.
Moon Over Point Place (1) - S2-E26
Continuity mistake: Red, Kitty and Midge are talking to Bob about Eric and Donna having sex. Red makes a point and Midge turns her head to look at Bob. The shot cuts and we see her from the side, repeating the head turn.
Answer: It's Ashton Kutcher's dog.