OC
An OC, short for Original Character, is a fictional character created by someone. In the remix world, the term also refers to OCs that have been brought out of their fictional universe and into the remix world, thanks to OC technology pioneered by Karl Marx and Doctor Joe.
OC vs. non-OC
Due to the fictional nature of the remix world, all characters in the remix world are technically OCs of someone in real life, added to the remix tree by Scratch users for fun. However, from the perspective of the remix world, their origins differ; some characters were in the remix world all along and thus are not considered OCs within the context of the remix world, while others entered the remix world through someone in the remix world using OC technology.
An example of the former is Dio, who existed in the remix world all along, despite from the perspective of real life having originated as a creation of Hirohiko Araki's who resided in the universe of JoJo's Bizarre Adventure. An example of the latter, meanwhile, is Avocado Ian, who was a fictional character created by someone else, and had the experience of growing up in another world, before eventually being transported to the remix world.