The Time Machine/Nightmare Fuel

The Book

 * The Morlocks feed and tend to the childlike, innocent Eloi.
 * Perhaps the most scariest part about the Morlocks are just how much more human they compared to the Eloi.
 * The Time Traveller's journey past the Eloi and the Morlocks at the end of the book.
 * The something
 * The fate of Weena.
 * The fate of Weena.

The 1960 Movie

 * The movie had quite a bit too. The aforementioned nuclear war is rather jarring (somehow the primitive effects make it worse in an Uncanny Valley way, but of course Your Mileage May Vary on that), plus.