Alternate Universe

In fan communities, an Alternate Universe (frequently abbreviated as AU) fanwork is one which significantly deviates from the canon story in some way. This, naturally, applies to fan videos every bit as much as it does to other creations.

Fanworks normally do deviate from canon in some way, but it's usually relatively minor; a fanfic will go in a different direction than the one canon takes because it's based on an ongoing TV show and they had no way of knowing for certain that their idea wasn't what would actually happen next, for instance. A mashup will rearrange a few scenes slightly to fit the lyrics of a song. When these still mostly mirror canon, they aren't necessarily AUs. Rather, an AU is what happens when something major has deliberately been changed.

When an intentionally impossible plot has been created, or something otherwise contradicts canon in a clearly purposeful way - when characters from several completely unrelated works of fiction which are all set in modern times are boarding the Titanic together, or characters who are siblings in canon aren't related, or when one character ends up looking like another. When the members of a perfectly mundane boy band are werewolf superheroes, and have always had lycanthropy and superpowers, or when a kindhearted scientist kidnaps the man who works with him willingly in canon, you know this is some kind of alternate universe. This is just as possible with videos as it is with writing, comics, or any other medium - even when the videos are made using imagery taken directly from the source materiel. With creative editing, mashups can do the things listed here, and make other assorted major plot changes which could cause them to count as AUs. With the magic of editing, any story can become any other story.

The most common forms of AU are ones where characters are placed into a different setting, ones where a specific major event has been changed (such as a character who dies in canon surviving), and ones where the characters play significantly different roles (such as a character being adopted into a different family).