Headcanon

A headcanon is a fan assumption made by fans to assume something within any main series Sonic canon, these usually happen within fans of the main game canon as the main game canon barely explain anything about the Sonic universe while another canon does a better job and people either ignore it because they hate it or don't know about it. This led to the creation of Sonic Headcanons on Tumblr. Headcanons are really canons they're actually fanfictions with a new word slapped on to them.