瑪麗蘇，即Mary Sue的音譯。瑪麗蘇（Mary Sue）一詞據說原出於國外的同人小說圈。某外國作者創造了一個名叫Mary Sue的虛構女主角在自編的科幻同人文里盡情YY，名聲大振，這個虛構名字也成為了具有代表性的心態名詞。Mary Sue即在同人文中虛構出一個真實劇情中沒有的主角，此主角往往很好很強大，與真實劇情中的人氣角色糾纏不清，曖昧不斷，桃花朵朵開。現在，瑪麗蘇還不光指同人文作者的自戀心態現象，也指原創文作者的心態現象。另外，也不僅限於女性作者。對於男女作者皆有的這種心態現象，統一簡稱為 「蘇」（Su）。
By Paula Smith
"Gee, golly, gosh, gloriosky," thought Mary Sue as she stepped on the bridge of the Enterprise. "Here I am, the youngest lieutenant in the fleet - only fifteen and a half years old." Captain Kirk came up to her.
"Oh, Lieutenant, I love you madly. Will you come to bed with me?"
"Captain! I am not that kind of girl!"
"You're right, and I respect you for it. Here, take over the ship for a minute while I go get some coffee for us."
Mr. Spock came onto the bridge. "What are you doing in the command seat, Lieutenant?"
"The Captain told me to."
"Flawlessly logical. I admire your mind."
Captain Kirk, Mr. Spock, Dr. McCoy and Mr. Scott beamed down with Lt. Mary Sue to Rigel XXXVII. They were attacked by green androids and thrown into prison. In a moment of weakness Lt. Mary Sue revealed to Mr. Spock that she too was half Vulcan. Recovering quickly, she sprung the lock with her hairpin and they all got away back to the ship.
But back on board, Dr. McCoy and Lt. Mary Sue found out that the men who had beamed down were seriously stricken by the jumping cold robbies , Mary Sue less so. While the four officers languished in Sick Bay, Lt. Mary Sue ran the ship, and ran it so well she received the Nobel Peace Prize, the Vulcan Order of Gallantry and the Tralfamadorian Order of Good Guyhood.
However the disease finally got to her and she fell fatally ill. In the Sick Bay as she breathed her last, she was surrounded by Captain Kirk, Mr. Spock, Dr. McCoy, and Mr. Scott, all weeping unashamedly at the loss of her beautiful youth and youthful beauty, intelligence, capability and all around niceness. Even to this day her birthday is a national holiday of the Enterprise.