The Chronicles of Narnia/Nightmare Fuel

Original Series

 * The illustrations of Tash.
 * "Always winter... and never Christmas!"
 * That is, when this is expanded, the idea of eternally being witheld from a ceremony of hope is horrifying.
 * The Truth in Television premise of The Lion, the Witch and the Wardrobe - being seperated from your family (one parent left in a civilian danger zone and one of which is directly fighting a war) because your enemies are raining bombs on your home every night - The Blitz

The Lion The Witch and The Wardrobe

 * The whole scene just before Jadis kill's Aslan.
 * Anytime the Witch turns some poor creature to stone. She even did it to a butterfly, a FREAKIN BUTTERFLY!

Prince Caspian

 * The hag (in the scene where they're trying to bring back the White Witch).
 * The minotaur being crushed under the gate and all the other Narnians being trapped.

Voyage of the Dawn Treader

 * The Sea Serpent. At first it just seems like a regular (if mildly scary) Sea Serpent but then partway through the battle... . It's effectivly combining several Primal Fears: fear of drowning at sea, a huge foe, and a fear of.
 * The Dark Island. In the book it's a vaguely creepy location that is never mentioned after it is visited. In the movie,