Nightmare Fuel / Howl's Moving Castle

• The Witch of the Waste, her blob things, and what happens to her in the room of lights.
• Forget the room of lights, what's even worse is when Howl makes his contract with Calcifer in the flashback, which puts into perspective exactly what those lights are, expands the ideas of what they can do almost infinitely, and worse, tells you that they are out there somewhere and not created or under the control of any magic user. Complete with unintelligible Ironic Nursery Rhyme.
• Howl's gradual transformation into a bird-monster, with it being harder, slower, and more painful to change back every time.
  • The dream Sophie had where she discovered Howl in said form and he says, "Go away." Enough to send chills up anyone's spines, especially if you recognize Christian Bale's Batman voice during the dream.
• That moment when Sophie thinks that Howl is dead, and the ring helps her to find him. Miyazaki always has great visual representations for magic, but liquid darkness is probably the most awesome (and one of the scarier) things that happen in anime.
• When the Witch of the Waste grabs Calcifer to get to Howl's heart. She begins to burn alive and scream in pain as Calcifer begs her to put him down. And poor Sofie, the only thing she can do to prevent her from burning to death is to dump water on them both effectively killing Calcifer and possibly Howl. Having to kill one friend or family member to stop them from accidentally killing another is real nightmare fuel.