Mary Sue is a pink alicorn OC created by Mad Munchkin. She was created as a gag for Mad Munchkin's "Why I hate Alicorn OCs" video, as a Mary Sue character, and after hearing the name "Mary Sue", she decided that would be her name.
Mary Sue truly believes that she is the greatest character created and can do no wrong. Often stating "I'm the best *blank* EVER, Cuz I'm Mary Sue."
Mary seems to have gathered a fanbase of her own.
Mary Sue is currently the announcer for the TF2 Analysis Anarchy team.