From Method to Madness - S3-E18
Revealing mistake: After the fight between Stewie and Olivia at the concert hall (followed by their breakup), Simon tells Stewie that the act without Olivia is "over" as he turns to walk off the screen. However, before Simon is even partially out of the shot, he completely disappears. (00:18:45)
He's Too Sexy for His Fat - S2-E17
Revealing mistake: During the scene when the people at the pool think Chris is a car sitting on the diving board, just before Lois moves out of the shot before the scene changes, her lips disappear for a split second. It's really fast but still easy to notice even without pausing or slow motion.
A Picture Is Worth 1,000 Bucks - S2-E11
Revealing mistake: When the hotel employee gives Peter the key to the room, the man's moustache turns yellow for a second.
Revealing mistake: Peter's right eye overlaps his nose when Lois reminds him about getting drunk off communion wine at church. This mistake was later referenced in "Back to the Pilot." (00:02:50)
Revealing mistake: When Brian and Stewie are on the tourbus, the scenery flashing past is just the same few buildings going by over and over. (00:14:25)
If I'm Dyin' I'm Lyin' - S2-E9
Revealing mistake: When one of the Gumbels is holding a pencil in his mouth and nodding repeatedly, the shaft of the pencil moves with his mouth, but the tip of the pencil (protruding from his hand) stays still. (00:17:35)
He's Too Sexy for His Fat - S2-E17
Revealing mistake: When Peter is in the grocery store talking to the Beautiful Peoples Club member, at one point Peter tilts his head, and his glasses disappear.
Revealing mistake: During the Ozzy Osbourne scene, there is a person in the audience with no mouth. (00:16:10)
Space Cadet - S11-E9
Revealing mistake: When Chris is giving them a tour of the shuttle, they are standing up normal. When they take off, they are still standing straight up. The shuttle goes straight up. You would be on your back at take off. They would never be able to stand straight up.
Revealing mistake: When Brian tells Brooke "I understand", after he thought he was being rejected, his left ear disappears for a single frame.
Revealing mistake: When Peter runs across the dock after getting out of the boat, a large chunk of his body is missing.
I Am Peter, Hear Me Roar - S2-E8
Revealing mistake: When Brian says "Well face it Peter, your attitude towards women isn't exactly enlightened", Brian's dog tag is the same color as his fur. It also stays still, even while Brian is moving his head. (00:11:10)
Revealing mistake: At Warsaw Temple, when Mort says "my bargain hunting Aunt Flo", production initials appear next to Brian's tail.
Revealing mistake: When Brian says "Our tickets were in the bags", half of his left hand is missing for a frame.
Revealing mistake: When Brian asks Peter how much money they're getting from welfare, his neck is drawn over his collar, making his head look like it's disconnected from his body.
Revealing mistake: Watch closely when Brian is demonstrating orbit. The apple can be seen to go through Peter's hand a couple of times. (00:07:50)
Revealing mistake: When Dr Hartman collapses, he falls off screen but as he disappears the animation is messed up in that he vanishes before the edge of the shot. (00:06:05)
Revealing mistake: When Lois says to become friends with the bullies and earn their trust, she raises her arm. When she does the animation is messed and and he arm merges with the table. (00:10:00)
Revealing mistake: Peter's right eye overlaps his nose when he's watching TV with his family.
A Picture Is Worth 1,000 Bucks - S2-E11
Revealing mistake: When Brian is shaking his head saying he will never go to the theater with Peter again, you can see part of his neck is missing. (00:09:10)
Suggested correction: It's actually his finger, not his dog tag.
In which case, his tag is missing.
Ssiscool ★
I agree, it's not his thumb because in the next shot of him in the same position, his tag is now there (or colored correctly) and his thumb isn't seen.
Bishop73
It looks like his thumb.