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Nightmare Fuel: The Green Mile
Can anybody watch Delacroix's horrifically botched execution and NOT squirm? Deliberately sabotaged by Percy, the sadistic guard, the scene goes on for several excruciating minutes. Instead of wetting the sponge that goes on the head of the person sitting in the chair, he leaves it dry, which interferes with the conductivity. As a result, instead of a relatively quick execution, the poor man's head catches fire and he dies an excruciating, tortuous death. Making it even worse is that John Coffey gets to feel everything Delacroix is feeling - every agonizing second - during the execution. Frank Darabont stated such horribly botched executions - albeit with a few less special effects - actually happened in Real Life. Part of what led to the electric chair being permanently retired.
Actually there are still a couple states that use the electric chair last I checked.
Coffey stating he can still hear "pieces" of convicts screaming in Old Sparky's chamber, long after they've been executed.
The flashback to how Wild Bill kidnapped the two little girls is also incredibly disturbing. Seeing it go from shots of a happy family to the family's hired hand threatening the girls before raping and killing them is like something out of a nightmare.