Continuity mistake: While Stiles and Scott are at the vet getting the black dust, the vet puts the mountain ash on the table and says it's for Stiles. Stiles picks up the bottle and it's in his hand. A shot later the bottle of ash is back on the table, but Stiles never put it down. Then the shot after they show it on the table, it's back in Stiles' hand and he sets it back down.
Revealing mistake: When Derek is training Isaac how to fight, Isaac is forced to repeat his approach many times, which results in him being smacked down by Derek. During certain shots, as Isaac is about to plummet to the ground, his hoisting wire can be seen. (00:12:35)
Wolf's Bane - S1-E9
Revealing mistake: When Jackson asks to "Inquiry-It!" on Melissa McCall's work computer at the hospital, the search engine is fake due to the search bar, making it clear it's a local file, not online: file://Users/jamesonfilm/Desktop/htm/newsearch.html. (00:09:14)
Continuity mistake: Scott and Stiles are walking past a hallway and they see three dead policemen. At the beginning, the arms of the second policeman are lying on his legs. After the shot of Scott and Stiles, that policeman's arms are now by his side.
Continuity mistake: In the scene where Scott is eating lunch and Allison comes and sits directly behind him, she sits down with a bottle of water and a bagged lunch. He has a tray lunch. Later on it the scene it changes: Allison has the tray lunch and he has the bagged lunch.
Plot hole: It is revealed that Malia has been living as a coyote for eight years but earlier in the season it's shown that all shape shifters lose their powers and becomes human during a lunar eclipse, which happened in the midseason finale. So why didn't Malia turn back?
Revealing mistake: When Kali disguised as a nurse holds up her fingers to count you can see her real nail under her claw.
Visible crew/equipment: After the Alpha wolf breaks through the movie rental window, it frightens Lydia, who was parked outside. As the camera pans closer to her face, a protective plastic cover hanging off the camera can be seen in the car window's reflection. (00:03:55)
Continuity mistake: When Scott and Isaac are at the vet after helping Issac's dog, Isaac walks toward the door talking about the lacrosse game. If you look at Isaac's head, sometimes there is a tiny piece of hair sticking up and sometimes there isn't. It switches back and forth between shots.
Deliberate mistake: Season 2, episode 10: After Matt is supposed to be dead underwater, you can see air bubbles coming out from his nose in a close-up, and in a far away shot his head is above the water so the actor can breathe.
Continuity mistake: Erica is wearing a wedding band in the close-up of her hand on the rock wall. It doesn't show up in any other shot. (00:09:26)
Character mistake: Theo applies a tourniquet to Lydia's torso in order to stop her from bleeding, he is later congratulated by Melissa who is a nurse. Tourniquets are not to be used for heads or torsos, only limbs.
Continuity mistake: Scott becomes more monstrous due to his new Alpha status. He even says that he now has extra fangs but later in the series, these fangs are gone with no real explanation to what happened to them.
Continuity mistake: The McCall house has its electricity shut off but at the end of the episode Scott's bedside lamp still works.
Character mistake: Tracy supposedly rips Lydia's tongue out to stop her from screaming. The only problem is that the tongue is not needed to produce a scream.
Continuity mistake: When Scott runs into his room after the party the shadow of the blinds can be seen all the way across the room, but in the next shot of the window, the blinds are only halfway down. The shadows cast doesn't match.
Other mistake: When Derek is tortured by Kate and turns into his wolf form his eyes don't glow.
Continuity mistake: When Derek finds the note on his car it's snowing, in the next shot it's not.
Character mistake: The poster advertising the Formal misspells Beacon Hills as 'Becon Hills'.
Second Chance at First Line - S1-E2
Continuity mistake: When Allison opens her locker, the things inside change from shot to shot.
