What creepy things have you either thrown at your players or had thrown at you?
One of my favorites was Annika. Annika was a young girl, about twelve years old, who had been kidnapped amid a rash of deadly nightmares through her town. The PCs determined that she had been kidnapped by a night hag, and went out to the forest where, according to lore, the hag laired. The hag told them that Annika was her daughter, and she was just transforming her in the method traditional of the night hags. The Freelance Police drove away, but didn't kill, the hag, rescued Annika, and used Remove Curse to dispel the unfortunate purple tone her skin had taken.
But, although Annika was still mostly human, she thought a big, well, haggishly. After the intial shock of being rescued, she was very calm, very collected and very intelligent. And one of the players just wanted to kill her, because he was sure that she was going to go for all of their throats. But she never did, which just made her all the creepier in his eyes...
I liked her. I think I'm going to have to bring her back.