Nightmare Fuel / Pokémon 3

• The Unown in general. And the fact that their otherworldly, reality-warping power ends up in the wrong hands. So many people, including Ash, are put in danger and almost killed as a result. Furthermore, the Unown are sentient enough to want to maintain Molly's illusionary world, so much so that they really aren't happy when she wants them to stop. No wonder many creepypastas, such as The Curse of The Unown King, paints the Unown as demonic villains.
• The dimension that the Unown transported Spencer to. He likely would have been drifting aimlessly through there for eternity.
• The way the Unown's powers, at Molly's command, affect Greenfield and those around her. A bulldozer that tries to break through the crystal barriers gets flipped and the man operating it narrowly avoids being imprisoned when the bulldozer becomes engulfed and crystalized.
• Entei's hypnotizing and abduction of Delia Ketchum. It's quite unsettling seeing Delia have her mind taken over and being essentially forced into being Molly's mother against her will, and as a result forgetting about her own real-life child. Luckily, she doesn't remain hypnotized for very long.
• Entei slowly becoming more and more enraged during its battle with Ash. Not helped by the fact that it can No-Sell practically any attack thrown at it. By the end of the battle, Entei was prepared to outright kill Charizard before Molly intervened!
• Molly's Mantine is pretty eerie with its constant smile and Voice of the Legion that makes even Entei's voice sound soft in comparison.

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