MacGuffin – Wikipedia, the free encyclopedia:
A MacGuffin is a plot device that holds no meaning or purpose of its own except to motivate the characters and advance the story. The device is usually used in films, especially thrillers. The term “MacGuffin” was invented by Alfred Hitchcock, who made extensive use of the device in his films. It is still almost always used in specific reference to Hitchcock’s plots, rather than as a general term for similar narrative conveniences in unrelated stories.
In the story I am writing, the genesis of it was a character who has now become a MacGuffin. But as I noted earlier, I’m just transcribing events as they happen. If I thought he was a main character, obviously I was wrong.