An original character (fem.) in fanfic or an original story, usually on the internet, who is far superior to all other characters. She is typically beautiful, intelligent, kind, and in all other ways "perfect". She usually serves as an important part in a pivotal plot element (ie: a prophecy) and becomes romantically involved with the author's favourite character in the story. The internet fiction world runs rampant with these characters.
dracosluvur: My character's name is Alienne Raven Jewel Sassandra Moonflower Romance Shimmer Honeybeam, she came to Hogwarts after being separated from her family in the U.S. and sold into illegal slavery in Japan, she's fluent in both languages and is part Fae. She has snow-white skin, black hair and sparkling eyes that change colour. She's tall, thin and busty, she fills in as the Charms professor sometimes and doesn't really have a house because she's just that unsortable so she has her own luxury room in one of the towers. Almost the entire male population adores her, staff and students, and she gets perfect marks and it figures that she is the one who actually kills voldemort.
SatiricalBanshee: AGH!DUCK AND COVER! MARY-SUE!