Nightmare Fuel / Alice Through the Looking Glass

• When the Hatter realizes Alice doesn't believe him about his family being alive, he shuts his eyes, disappointed. When he opens them, it's frighteningly obvious he's not the same cheerful, kooky person he usually is.
• The Minutes. They start off as the cute little Seconds, but then they combine to form larger, more intimidating machines with glowing red eyes and deep voices.
• All of Underland, and everyone in it, at all times, becoming an eternally stagnant heap of rust. Thank goodness it didn't last.
• Cheshire, who's still smiling as he dies.
  Cheshire: Time's up...(grins insanely and closes his eyes as the rust forms over him)
• The rust itself is quite creepy to look at, and the way it moves and and forms little points is disturbing.
• The present Iracebeth revealing herself to her past self and then immediately rusting over. Young Iracebeth screams in terror before rusting over as well.
• Alice being put into the asylum and almost given some medicine that probably would have repeatedly been administered to her, keeping her constantly sedated. Female hysteria diagnoses were still commonplace in her time, and a purportedly "mad" woman would never leave an asylum and would be treated very inhumanely. Mental illnesses still aren't understood today, and there was zero understanding back in the 19th Century. Luckily Alice escaped.
• We briefly see the dead body of The Knave of Hearts... with a knife in his chest!