Continuity mistake: When Rachel is tucking Aidan into the bed at Max's house she puts a red blanket on him and then a brown blanket on top. Then during the next shots the red blanket goes from slightly visible to completely covered by the brown one and back again to being slightly visible. (00:39:15)
Continuity mistake: In the first Ring it is revealed that Samara was in fact the Morgans' daughter. They showed her birth certificate with the Morgans as the parents and then the father before killing himself yells that his wife wasn't supposed to have a child. Yet a huge part of the second movie is about how Samara is adopted and Rachel talks to her real mother in an asylum. Um... What happened to what was found out in the first film?
Continuity mistake: When Rachel is placing Aidan into the bathtub slowly in order to try and rid Samara from his body, as she places him in the water, how deeply she has him in the water keeps differing from each shot. (01:26:40)
Continuity mistake: When Rachel finds Aidan standing at his bedroom wall and the image of a tree begins to burn in the wallpaper, she runs over and tries to pull him away. As she does this, the globe sitting on the desk beside them rotates itself between shots. (00:35:45)
Continuity mistake: When Jake enters the living room to bring the drinks to Emily, the magazine and remote sitting on top of the two books moves between shots. (00:01:35)
Continuity mistake: When Aidan is in the bathroom at the fair, he turns a faucet and then he walks across and turns another. After turning the second one, the faucet changes position from the wide view to the closeup, evident by the ridges on it. (00:27:45)
Continuity mistake: When Rachel is talking to Aidan at her Daily Astorian office, when she asks him if he knows why Samara is back, she puts her hand on his face. In the very next shot it's down in her lap. (00:37:05)
Continuity mistake: When Rachel is burning the videotape in the canister out in the field, she throws the tape on the fire with all of the reel pulled out and sitting on top of the case. In the next shot the reel is no longer visible on top of the video. (00:19:30)
Continuity mistake: After Aidan comes downstairs and sits at the table for dinner, he is flicking through his photography folder. In the shot when Rachel walks away from him and goes back to the oven, there is no plate at Aidan's placemat, yet it is there in every other shot before and after. His drink also moves without him touching it. (00:09:05)
Continuity mistake: When Rachel sits next to Aidan as he is in the hospital bed unconscious, as the shots change, the amount and position of the wires next to his head (to his right) keeps on changing. (00:50:35)
Answer: The deer were attacking the car because Aiden was in the car. Aiden was possed by Samara at the time and Samara makes animals go crazy.