There have been a lot of Harry Potter theories, ranging from the ridiculous to the strange to the horrifying.

I have composed a list here.

Please comment any other theories you know of that I've missed. :)

Also: there are major spoilers in some of these. Next to each one, if there is a spoiler, I will write the book that it spoils, so if you haven't read that one: skip that theory.

1. The Dursley Family is Justified (Spoils Deathly Hallows)

This is one of my favorites, by the way. Now, we all know that Horcruxes often corrupt people (the medallion, Riddle's diary) and Harry is, as it was revealed in the seventh book, a Horcruxes. So wouldn't it make sense that Harry has a 'bad energy'? This could explain why the Dursleys were so mean to him - yes, they hated Wizards, but some people needed more of an explanation and deduced that Harry simply annoyed people.

2. Draco Malfoy is a Werewolf (Minor spoiler)
Lucius Malfoy pissed Voldemort off later in the series, and what else would He-Who-Shall-Not-Be-Named do then send Greyback after Lucius's son? Draco was bit after his fifth year ended.

3. Dumbledore is Ron
Okay, this one is plain crazy, but I love it. This theory states that Ron is a version of Dumbledore, gone back in time to help out Harry. Think about it: Ron and Dumbledore are described as having the same appearance... Yeah, no. This I still an insane theory.

4. Harry is Crazy
This one is really sad, and made me half-depressed for an hour. The theory goes like this: Harry went so crazy because of his uncle and aunt that he invented a whole world for himself, a world where magic existed... And this theory actually makes sense. Harry imagined a world where he was the Chosen One, where he defeated a powerful wizard, where his parents died for good, where he had friends and was famous. It's sad, but even J.K Rowling approves. She said this was her favorite fan theory.

Anyways, do you have any other Harry Potter theories to share?