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)
Neogenic Nightmare Chapter 11: Tablet of Time - S2-E9
Continuity mistake: When Dr. Connors starts transforming into the Lizard after being blasted by the robot, the sleeve of his lab coat magically becomes tattered at the same time his hand transforms. Subsequent shots also alternate with his sleeve being tattered and pristine as well as his hand being reptilian and normal.
Continuity mistake: When Mandarin pulls the lever to initiate the decomposition sequence, the jewels on his rings are shown to take up about half the width. When the shot changes, the jewels are suddenly as wide as the rings themselves, if not wider. (00:18:20)
The Origin of the Fantastic Four: Part 2 - S1-E2
Deliberate mistake: When the Thing is doused with the chemical that reverts him back to human form, he somehow also is suddenly wearing a T-shirt, jeans with a belt, and shoes, which is illogical since the Thing wears a speedo with no shirt and is barefoot. (00:05:35)