A feature film, or the big time. You even have famous directors who do prototype short films to see how a full length version may turn out. They may find it hard to get producers on board, so to attract interest, they throw up a concept. Like the short Saw movie where you see the bear trap. It was not canon, but it set up the first movie, which then became a profitable franchise, even if critics were a bit iffy on some of the sequels.