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The creepiest character I've read to date is Humbert Humbert from Lolita. I was introduced to him via book on tape (read by Jeremy Irons aka Scar from The Lion King) in my car on the way to work and was seriously worried that if I got pulled over, I might go to jail on suspicion of severe creepiness just for listening to it.

All of my creepy characters are based off one person in my life. Without giving too much information, because he is a human being, this guy seemed to be the ultimate creep--in the way he always showed up when you didn't want him to (which was any time), in his appearance, in the way he talked and in the way he looked at you. You always had this sneaking suspicion that he had just done, or was about to do something weird, perverted and/or illegal. And he didn't know how to take "no" for an answer. He was always trying to hug or touch people, often getting yelled at or slapped in the process. If you kicked him out of your party, he'd linger outside the doorway, peeking in, trying to make conversation with whomever would respond. And if no one responded, he seemed okay with that. He always trying to be part of something, which made me wonder about how he'd gotten to that place--what was his home life was like. I started wondering how he'd been treated as a small child, or how much, if any, attention he got from his parents. If he even had parents. I wondered who loved him and why he was so passionate about the things he was passionate about. I wondered what his house looked like--his bedroom.

I know, right? Who's the creep now? (Me.) But thinking about these things has helped me understand people who appear to be creepy. They're just people who never learned how to process and deal with the world. Whether they're a shy creep (George McFly) or a loud creep (Biff Tannen), creeps don't just materialize out of thin air. They are born of creepiness, heir to creepiness and parent to creepiness. And just like my insane and douchey characters, they come from somewhere.

See Top Ten Creepy Characters from movies.