Nightmare Fuel / Beren and Lúthien

• Tevildo allows mice to dwell in his fortress because he likes playing with them "for his own private sport".
• When Morgoth's forces invade Dorthonion, his power desecrates and curses the land so the lush forests become a dreadful, dark enchanted woodland.
• Beren crosses the Mountains of Terror and the Valley of Dreadful Death, which are home to the brood of Ungoliant (the light-devouring spider-like eldritch abomination), and other fell things warped and mutated by the magic clash between Sauron and Melian. Beren, the only Man who walked into Angband voluntarily and lived to tell the tale, will always refuse to talk about his journey because he is permantently haunted by the memory of the it.
  Sheer were the precipices of Ered Gorgoroth, and beneath their feet were shadows that were laid before the rising of the Moon. Beyond lay the wilderness of Dungortheb, where the sorcery of Sauron and the power of Melian came together, and horror and madness walked. There spiders of the fell race of Ungoliant abode, spinning their unseen webs in which all living things were snared; and monsters wandered there that were born in the long dark before the Sun, hunting silently with many eyes. No food for Elves or Men was there in that haunted land, but death only.
• Finrod, Beren and his men are captured by Sauron, thrown into the dark pits of the Isle of the Werewolves and tortured. Finrod and Beren's ten companions, who refused to abandon their king when everybody else did, are eaten one-by-one by werewolves:
  These much he pondered and bethought,
  and in their woeful chains them sought,
  and threatened all with dreadful death,
  if one would not with traitor's breath
  reveal this knowledge. Wolves should come
  and slow devour them one by one
  before the others' eyes, and last
  should one alone be left aghast,
  then in a place of horror hung
  with anguish should his limbs be wrung,
  in the bowels of the earth be slow
  endlessly, cruelly, put to woe
  and torment, till he all declared.
  
  Even as he threatened, so it fared.
  From time to time in the eyeless dark
  two eyes would grow, and they would hark
  to frightful cries, and then a sound
  of rending, a slavering on the ground,
  and blood flowing they would smell.
  But none would yield, and none would tell.
• Sauron transformed into a frightful humongous werewolf to slay Huan and capture Tinúviel. When Sauron was defeated, "immediately he took the form of a vampire, great as a dark cloud across the moon, and he fled, dripping blood from his throat upon the trees, and came to Tar-nu-Fuin, and dwelt there, filling it with horror."
• Huan grabs two werebeasts' hides from Sauron's ruined tower so Beren and Lúthien can change their shapes and make it to Angband unbothered. Beren wears the pelt of Draugluin, the first Werewolf, and Lúthien transforms into Sauron's courier Thuringwethil, a large vampire with literal iron claws. Their appearance is so awful that all things flee before them during their journey to the North.
• Sauron wanted to fulfill Huan's prophecy by transforming into the mightiest Wolf ever, but he merely turned into a giant wolf. Carcharoth is the mightiest and biggest wolf that should ever walk the world. Hand-fed by Morgoth with Elvish and Man flesh, the heroes are acutely aware of his size, his gleaming red eyes, his sharp fangs, his flaming tongue and his poisonous bite every time they face him.
• Beren and Lúthien go into Angband, which is described as a many-tunnelled tomb or labyrinthine pyramid. Everywhere they can see horrible shapes carved into walls and columns, hear the rumour of "thunderous forges", listen to awful laughter and smell the stench of burning smoke and foul vapors. And in the center of the main hall, surrounded by Balrogs and Wolves and tiny metal snakes -prototype dragons-, Morgoth is lounging in his foul throne, drinking blood.
• When Morgoth finds Lúthien sneaking around his fortress, his rants about "a pretty toy for idle hour", "crushing a beautiful flower" or "slaking the sting of his hunger with a morsel" make clear that he intends to rape her on the spot.
• When Morgoth awakens and realizes that Lúthien and one Silmaril are missing, he gets mad. As Lúthien and Beren are being flown to safety, the Elf maiden feels "below them suddenly thunder rolled, lightnings leaped upward, and the mountains quaked. Fire and smoke belched forth from Thangorodrim, and flaming bolts were hurled far abroad, falling ruinous upon the lands; and the Noldor in Hithlum trembled." That is what a severely weakened Morgoth makes when he is merely throwing a tantrum. And the Noldor thought they could kill him by poking him with pointy metal sticks?

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