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Nightmare Fuel: The Silence of the Lambs
The whole serial killer plot. The part with Catherine in the well, where the camera pans up and you see bloody trails and the severed fingernail from the last girl who tried to climb out and failed, scares me even after seeing that film several times.
The book has the added note that Catherine remembered reading about a girl's broken fingernails before that in an article about Buffalo Bill and realizes who has her.To add to the scene, Ted Levine's completely inhuman and mocking screams just pile on the horror.
Also, Buffalo Bill himself is insanely creepy.
What is particularly brilliant about this scene is that it shows a terrifying situation, something horrifying, sickening and disturbing... and yet something that is instantly quotable and amusing to almost anyone who has seen it. That's scary.
The scene where Hannibal beats the prison guard to death.
Including a later scene where other guards storm the prison room and find said prison guard suspended in a backlit crucifixion position with a big hole in his stomach, innards missing Together with the music, a Revolting Moment of Awesome... The whole part was terrifying. While transporting the surviving guard (who suffered severe facial lacerations) in the elevator, blood starts dripping down and he realizes he's on the roof of the the elevator. After he ignores the warnings of the SWAT team on the floor above, they shoot him in the leg without him even flinching. As soon as they open the hatch from inside the elevator, it cuts to the ambulance, where the guard sits up and we find out Hannibal had taken his clothes, and was using his face as a mask.
The sequence in Hannibal where Mason Verger is shown gleefully (thanks to the drugs Lecter gave him) cutting his own face off with a piece of broken mirror. Bonus points for showing Lecter feeding it to the dog. The flashback itself is filmed with a very surreal and disturbing style and features Mason wearing a bizarre sex mask and swinging like a corpse on a fake noose. Creepy.
Also, Mason Verger himself. His Nightmare Face is something short of it. A child-molesting sadist who brutally raped his own sister. Once karma catches up with him in the form of Hannibal Lecter, the crippled Verger resorts to verbally and emotionally abusing children. Then he drinks martinis made from their tears.
Three Words: Dr. Hannibal Lecter. Not only is the man a known serial killer and cannibal, he's also a genius. That's not what makes him scary. What makes him scary is his Affably Evil personality. He has a charm and way of speaking to people as if he were engaging in everyday conversation with guests at a party rather than a trained FBI agent. Unlike the other inmates that Clarice encounters in the prison, Hannibal doesn't scream obscenities at her, he doesn't threaten to kill her, nothing like that. No, instead, he talks calmly to her as if she were one of his former patients or an old friend. The utter calmness yet meanace in his voice shows that he is not someone you want after you.
"What does your father do? Is he a coal miner? Does he stink of the lamp? You know how quickly the boys found you. All those tedious, sticky fumblings in the back seats of cars, while you could only dream of getting out. Getting anywhere, getting all the way to the F...B...I." Jodie Foster's shocked reaction is genuine and rightfully so. It shows that Dr. Lecter is not someone to be taken lightly and that he knows how to get inside someone's head.
The (in)famous line "A census taker once tried to test me. I ate his liver with some fava beans and a nice chianti."
A creepy fact dropped early in the film, that during one rampage, Lecter's pulse never went above 85.
Lecter's horrendous taunts to Senator Martin in both the book and the film of The Silence of the Lambs.
Lecter's sense of smell. "You use Evyan skin cream...and sometimes you wear L'air du Tempsóbut not today." That moment is both weirdly erotic and incredibly creepy.