The One With the Sharks - S9-E4
Revealing mistake: While Monica and Rachel are talking about Chandler's "jollies to Jaws" Rachel's wearing a colorful flowery top, and after Joey walks in just as Monica takes her seat at the table in the closeup, it's Jennifer Aniston's stand-in, wearing a blue top, who is seated beside Monica. Rachel's hair is wavy in the flowered top, but straight in the blue top (viewed in widescreen). (00:12:22)
Visible crew/equipment: When the son of the accident victims is being led through the trauma rooms to see his parents' bodies, you can see Laura Innes crouching under a table in the background directing the scene. Innes was the director of this episode and it was established that this episode took place on her character's day off. Therefore, she should not have appeared in front of the camera at all. (00:32:30)
Sins of the Fathers Chapter 3: Attack of the Octobot - S3-E3
Continuity mistake: When Doc Ock is being taken away in handcuffs at the end of the episode, his mechanical arms are missing. The arms were fused to his spine, so the police couldn't have confiscated them.
Silence My Companion, My Death Destination - S1-E4
Continuity mistake: When the Stark Industries tank is engaging its weapons system against the Hammer Industries vehicle, there are several rock formations immediately behind it. A couple of shots later and the tank is suddenly has no rock formations near it. (00:01:56)
The Origin of the Fantastic Four: Part 1 - S1-E1
Continuity mistake: When Sue is holding up the book for Dick Clark, her right hand is on the bottom of the book on the spine side, and her left hand is in the upper right corner. When the shot changes, her right hand is suddenly closer to the top-left corner. (00:02:18)