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Nightmare Fuel: [REC]
The last 20 minutes or so of the first film. Think of it this way: You're stumbling around in pitch blackness, dependent on the night vision on a guy's video camera in order to see any of the bad things you know you're locked in the building with... which are all demon-possessed rage zombies. Sweet dreams.
The Medeiros girl. Emaciated, tall, animalistic, and possessed by demons.
Any time Jennifer is shown after she becomes infected, especially the way she just suddenly appears behind everyone else as they're looking for her.
[REC]3: Clara becoming an infected and ripping out Koldo´s tongue and lips as they kiss. It even becomes worse by the fact that they are immediately shot and killed by the soldiers who are surrounding them.