MacGuffin

Etymology
Used by, as an arbitrary Scottish surname. The actual name comes from :. See also Wikipedia's.

Noun

 * 1)  A plot element or other device used to catch the audience's attention and maintain suspense, but whose exact nature has fairly little influence over the storyline.

Statistics

 * According to data collected by Forebears in 2014,  is the 736,413st most common surname in the United States, belonging to 13 individuals. Less common than the form.