Nightmare Fuel / I Am Legend

The book

  • The sole concept of being the last human alive on Earth. At least in the latest film adaptation, Neville is aware that there were few millions of people who are naturally immune all around the world and there is a good chance some of them are still alive. Maybe not around New York, but someone somewhere could survive, giving a sliver of hope. Not so much in the book, where he doesn't even know what is happening early on.
  • Your own, beloved wife coming back from her grave. A grave you've put her in yourself. And yearning for your blood. And still being apparently at least semi-sentient, so it's not just a mindless, blood-thirsty undead you can rationalise into killing in self-defense.

The 2007 film
  • Neville going into a darkened building, a likely place to find lots of Infected, to search for his dog. He's so obviously terrified you can't help but be frightened with him.
  • The zombies look very frightening.
  • One can't help but feel unnerved when Neville finds an immobile mannequin standing in the middle of the street, far from where it was supposed to have been resting.
    • What's worse? If you look carefully at Fred the Mannequin as Neville focuses his attention on it...its head slowly moves to look at Neville, or from the camera's perspective, you. It's never explained why Fred was able to move its head, but it's likely due to Neville losing his grip on reality.
  • The news reporter describing the ongoing mutations being caused in those treated with the Krippen virus, showing how something that should have been a source of hope has gone so badly wrong.
    Reporter: So far, almost 5000 patients treated with the retrofitted virus have begun exhibiting symptoms resembling the early onset of rabies. Twenty five patients have already died.
  • The evacuation scene, and seeing the panic as hundreds of people are trying to flee New York.