Fandom School (1st period): Fanon

Today is a snow day (even though there is no snow), so I am very happy. Anyway, here's Fandom School. The subject is canon and the topic is fanon.

So what exactly is fanon? Fanon is like canon, except that it's created by the fans and not the original creator. Sometimes fanon conflicts with canon, and sometimes they coincide. Fanon doesn't have to be agreed on by everybody, but it is accepted by the majority of the fandom.

What can be fanon? In many cases, ships are fanon. For example, Johnlock and Merthur are accepted by most fans, even though they are not canon (in fact, Johnlock has canon against it). Events can also be fanon. In the LoTR fandom, it's fanon that Legolas and Aragorn knew each other before The Fellowship of The Ring. The Big Bang Theory has the fanon that Sheldon has Asperger's Syndrome.

What's really exciting is when fanon becomes canon. For example, fans began calling Voldemort "Voldy", which became canon in The Deathly Hallows. And now we know that a Weeping Angel will turn to stone if it sees its own reflection. And in Dilbert, the cat character was unanimously named by fans as Catbert, and creator Scott Adams decided to confirm that.

What examples of fanon do you know of?