In the years since the final Harry Potter book was released (and indeed, the final Harry Potter film) there have been countless weird and wonderful fan theories. Many of these range from the preposterous to the ludicrous, including theories about Ron being a time travelling Dumbledore, about Harry and Hermione being siblings and that Professor McGonagall is in fact a Death Eater. What there have been less of is genuinely convincing fan theories...but they are out there. After all, J.K. Rowling's world is so vast and so detailed and so much material never made it into the novels themselves, as Pottermore attests that there are undoubtedly bits and pieces left behind that can be assembled to form a much bigger picture. On top of that, there are details that have been purposely hidden from fans like the complete nature of the creation of Horcruxes, for example. Not only that, but J.K. Rowling enjoys interacting with fans on Twitter, occasionally throwing fuel on the fire and even endorsing some of these great theories.