The human centipede turned me on alot. Why did that happen?

Fantasies are fantasies and everyone has strange ones from time to time. Most people just would never admit to it. That's normal. Who cares what you're fantasizing about when you are by yourself or with a consenting partner? As long as you aren't hurting anyone you can fantasize about whatever you want! You shouldn't feel ashamed. There is nothing wrong with you.