mcguffin
/məˈɡʌfɪn/
noun
- An object, event, or character in a story that serves as the trigger for the plot but is ultimately unimportant in itself.
- In many spy movies, the secret formula is just a MacGuffin that gets the action started.
- The missing necklace turned out to be a MacGuffin; the real story was about the characters' relationships.
- Directors often use a MacGuffin to give the hero a reason to go on an adventure.