WARNING: Spoilers are unmarked.
- Christine herself. A dangerous, hate-filled sentient vehicle that will not hesitate to kill anyone who either crosses Arnie or gets in the way of their twisted relationship.
- As if that wasn't enough, it would appear that she is completely indestructible, so no matter how hard you try to get rid of her, she will always come out on top in the end.
- The fact that her origin is never explained. While the novel goes into detail about her history with LeBay (and all of it is deeply fucked up in a way that only Stephen King could have imagined), the exact nature of how a sentient car came into existence is left ambiguous.
- The scene where Christine tries to murder Leigh in a fit of jealous rage.
- Christine's massacre of Buddy Repperton and his gang. While they all 100% deserve it, it's still horrifying to watch.
- The very concept of what's happening to Arnie. It's almost non-existent in the movie, but it's pretty blatant in the book, if you read between the lines.
- Arnie is being possessed by the ghost of Roland D. LeBay. It starts off in subtle ways, like Arnie combing his hair like a 50s greaser or listening to 50s music, all of which you could easily put down to simple things like personal taste. But it keeps going, as Arnie starts treating his girlfriend badly, yelling at his family, mistreating his best friend, and even breaking the law by smuggling fireworks across state lines. The ultimate sign is when Arnie injures his back at work, but can't quite remember HOW he injured it... except that now he needs to wear a back brace, just like LeBay.
- It takes a step into true nightmare territory towards the end, though, in a sequence where Dennis confronts Arnie in the school parking lot, calling him out on his bullshit and pointing out just how much he knows. Suddenly, the facade breaks and Arnie comes back, frightened and pleading with Dennis to help him. Then the walls are back up, and LeBay is talking again. It adds a huge dose of And I Must Scream to the story, making it even more frightening.