Hogwarts is stuffed full of as much mystery as a box of Bertie Bott's Every Flavour Jelly Belly Beans, so it's no surprise to find so many fan theories out there!
And so we thought, well, why not, let's round-up the weirdest fan theories and bring you the best of the bonkers concepts the wizarding world has ever known!
Yep, we know, it sounds hard to believe but think about it - broomsticks and flying umbrellas? Something smells distinctly fishy (and we're not talking about Hagrid's breakfast).
He was never very good a getting to class on time so how exactly would Ron make it to the future and back? Well, where there's a wizard, there's a way!
Come on, don't pretend you haven't though this before! He's always wearing black for a start - but then again, isn't every teacher at Hogwarts? Well, apart from Ms Umbridge, that is.
This fan theory reckons the reason for the Dursleys being so mean was down to Harry being Voldemort's horcrux but we reckon the Duresleys would be mean whatever!
We all know J.K. Rowling wrote the books, but was she more than a really good writer of wizards? Well, if this theory is to be believed, J.K. Rowling was actually - wait for it - Rita Skeeter! Yep, apparently she just wanted to tell us muggles the world of wizards and witches was real. And come on, who doesn't believe in Hogwarts?
We know Professor Lupin went a bit wild when the moon came out but who'd have guessed Draco was a werewolf? What? You'd already guessed? Well, we're not surprised really, because Draco's definitely a monster!
Look, we know - everyone knows Harry and Hermione should have got together so there must have been some potions involved to make Harry fall for Ginny, right? Well, unless it was true love, that is. Aww!
We've all dreamed of Hogwarts but what if Hogwarts itself was just Harry Potter's dream? That would be a nightmare and not in a good way!