Continuity mistake: At Ryan's surprise welcome back party, Clark puts his right hand over Ryan's shoulder as he asks him "you knew about this didn't you?" Cut to a different angle as Ryan responds "I was tempted too" but now Clark's hand is no longer on Ryan's shoulder. Cut to Clark then back to Ryan and now Clark's hand is back on Ryan's shoulder.
Audio problem: After Ryan collapses at Lex's, he and Clark are talking while Ryan is in the hospital. In the shot of Clark as Ryan says "I know what's wrong with me." Ryan's mouth is visible and you can see that he is not speaking the line as we hear it.
Continuity mistake: Lex brings some comic books to Ryan at the hospital. He holds all of them with his left hand. He then shows 66 of the comic to Ryan and holds it with both hands. Cut to a different angle and now he is holding the comics with just his left hand once again.
Continuity mistake: After Clark finds out that Ryan is dying, we see him holding a comic book in the farm. His dad then arrives and he turns to look at him. He places his left hand to his side as he holds the comic book in his right hand. Cut to a different angle and now both his hands are together in front of him.
Revealing mistake: When we see Ian split, his two selves are supposed to be looking directly at each other but they're really both looking slightly to the right. It's hard to focus when there's really nothing there. (00:15:45)
Continuity mistake: When Clark lifts Lana back onto the bridge, from a shot from above, we see that Lana puts her left leg onto the bridge into a sitting position. They then cut to a different angle but now both her legs are still dangling and she eventually puts her right leg on the bridge first.
Continuity mistake: The shot with Ian pulling Lana out of the car shows the shadow cast on the bridge covering half the road. A few seconds later, after Chloe gets free of the Ian that has her, the shadows on the bridge are much shorter.
Continuity mistake: At the Talon during Chloe's interview with Ian, Ian holds the mug by its ear, but in the next shot Ian is no longer holding the mug by its ear but by the mug itself.
Factual error: When Ian throws the unconscious Chloe over the edge of the dam we see her falling down as Clark falls with her. However, Chloe's body position is unnatural for someone who is falling while unconscious. Her head/body is arched backwards when air resistance should have forced her body to become level/straight.
Continuity mistake: When Ian is dragging Lana towards the dam, his double can be seen in the background dragging Chloe. The double is on Chloe's right side pushing her. Cut to a close up as Chloe says "Ian you need help" but now the double is behind Chloe and is pulling her.
Continuity mistake: When Ian confronts Mr. Frankle about his grade, the teacher removes both his gloves and is about to raise his face protector. Cut to a different angle but now he has his right glove back on.
Skinwalker - S2-E10
Continuity mistake: While he is being attacked by the wolf the foreman fires the flare gun with his arms spread, meaning that it would fly at an angle away from him. He then sees it arcing back from below toward him, impossible unless the flare changed direction and location in the air. (00:02:20)
Skinwalker - S2-E10
Plot hole: Chloe says the coroner found teeth marks on the foreman's bones. During the attack, at the beginning of the episode, the foreman only got a couple of scratches on his face and the rest of his clothes were perfectly fine and hadn't, in any way, been torn up. It would have taken the wolf tearing through the clothes, through the skin and, finally, through the muscle to leave any teeth marks on the foreman's bones and that did not happen.
Skinwalker - S2-E10
Visible crew/equipment: After Joseph gets locked out of the construction site, the worker, who locked him out, walks away. All the other workers at the site are gone, but when the shot returns to Joseph you can see the shoulder of someone standing between Joseph and the gate even though there should be nobody there.
Skinwalker - S2-E10
Continuity mistake: When Lex is talking to Lionel outside the building site at the end, Lex's sunglasses disappear while the camera is on Lionel and reappear when back on Lex. This happens after Lionel turns to face slightly behind Lex and continues throughout the rest of that exchange.
Skinwalker - S2-E10
Visible crew/equipment: After Kyla dies the scene goes to the construction site as Martha and Lionel get out of a SUV. As Martha gets out you can see the camera and film crew reflected in the window of the SUV.
Skinwalker - S2-E10
Continuity mistake: When the wolf jumps out the window of the Luthor mansion there is no blood on the glass shards that are left in the window. As Clark goes to the window, there is, all of a sudden, a lot of blood present on the glass.
Answer: The kryptonite only creates mutations when it reacts with the environment and an individual. Remember, the FDA and several environmental groups did check out Smallville after the meteor shower, but found no danger in the rocks. Obviously they're not always emitting mutating rays, or all the flora and fauna of the surrounding area would be horribly mutated.
Phoenix