See [[NightmareFuel/TheHobbitAnUnexpectedJourney here]] and [[NightmareFuel/TheHobbitTheDesolationOfSmaug here]] for nightmare fuel related to the Creator/PeterJackson [[Film/TheHobbit films]] ''Film/TheHobbitAnUnexpectedJourney'' and ''Film/TheHobbitTheDesolationOfSmaug'', respectively.

!!'''The Book'''
* The description of Mirkwood, particularly at night. [[TheWallsHaveEyes Surrounded by eyes just watching them, particularly the insect eyes]]. And if fires were lit, more eyes came and moths flapped everywhere.
** Also in Mirkwood, the [[PrimalFear slow dwindling of their supplies until they were hopelessly lost without food or water]].
* Smaug's thoughts and dreams of greed and violence.

!!From the [[WesternAnimation/TheHobbit Animated Film]]:
* Far from being bumbling and slow witted like in the Peter Jackson film, the trio of trolls are actually cunning and intelligent, as they instantly pick up on the fact that if Bilbo was there, then he'd have company. Heavily implied with their last conversation, they had a pretty good idea of what they were cooking and just arguing about the method, the worst being eaten "raw". Only by Gandalf's intervention, that the company was spared.
* Gollum, both in appearance and Brother Theodore's voice work. Until Andy Serkis came along and made the character his own, he was the definitive Gollum, and some fans say still the creepiest.
* The goblins' first appearance when they appear to be getting closer and closer in the dark.
* The "Riddles in the Dark" music.
-->''It cannot be seen, cannot be felt, cannot be heard, cannot be smelt, it lies behind stars and under hills, and empty holes it fills, it comes first and follows after, ends life, kills laughter. The answer is dark. The dark. Dark...''
* The spiders of Mirky Wood are bat faced AxCrazy fiends that cocoon and then eat their victims alive, especially creepy with their big blue, pupil-less eyes.
* While Smaug's appearance is silly, when he goes berserk, he is quite frightening for sure!