Fun Fact Friday: "Mary Sue"

This week's random reference question falls under the "never heard of it, once you hear of it now you hear it everywhere" category.

The question:
What's a Mary Sue?

My follow-up question:
Is Mary Sue a thing, or a person?

The follow-up answer:
I don't know ... somebody called one of my characters a Mary Sue ... but her name's Dionne.

The answer (after several more rounds of follow-up questions):
"Mary Sue" is a pejorative term used to describe a fictional character who is too good to be true, and typically suggests wish fulfillment on the part of the author (by being stunningly beautiful, magical, etc.) If the character is male, he's a "Gary Stu."

The term originated in Star Trek fanfiction, and now pops up in most dicussions of fanfiction (go Google Harry Potter and Mary Sue to see what I mean -- if you write HP fanfic you can even take the Harry Potter and the Mary Sue litmus test to see if you're committing "Mary Sueism").

Learn more at Wikipedia, a nice long article with an etymology and examples of Mary Sues.

The randomness:
I'd never heard of a Mary Sue before this question (not being a fanfic reader or writer myself) but a few days later it cropped up on my favorite reader's advisory dicussion list, where I was relieved to see I wasn't the only librarian in the dark re: Mary Sues.

So now I'm having fun witch hunting for Mary Sues in books and movies ... every female character ever to appear in a James Bond movie? Mary Sue! Tom Cruise's Ethan Hunt character in Mission Impossible? Gary Stu!