MacGuffin

In fiction, a MacGuffin (sometimes McGuffin) is an object, device, or event that is necessary to the plot and the motivation of the characters, but insignificant, unimportant, or irrelevant in itself. Thus, the use of a MacGuffin in a narrative is a plot device. The term was originated by Angus MacPhail for film, adopted by Alfred Hitchcock, and later extended to a similar device in other fiction. The MacGuffin technique is common in films, especially thrillers. Usually, the MacGuffin is revealed in the first act, and thereafter declines in importance. It can reappear at the climax of the story but may actually be forgotten by the end of the story. Multiple MacGuffins are sometimes derisively identified as plot coupons—the characters "collect" the coupons to trade in for an ending.