MacGuffin - A plot device in the form of some goal, desired object, or another motivator popularized in the 1930s by Alfred Hitchcock: "Taken from a story about two men on a train. One man says, 'What's that package up there in the baggage rack?' And the other answers, 'Oh, that's a MacGuffin'. The first one asks, 'What's a MacGuffin?'"