So I finally decided to break down and read (re:marathoned) Attack on Titan.
Its a smiley tag used over at Something Awful. Specifically the one with the words "Oh No! Holy Fuck!" shooting out of a television screen and knocking over the smiley, couch and all. My guess is that it originated in The TV IV forum specifically (given that they share the same name, plus I think the IV stands for Intravenous as in those pouches that drip fluids into you at the hospital; and TV should be self explanatory).
The long belated point was that I wanted something to better express my feelings with so I made due with this place's lack of smileys by substituting for another. Really, they should've sent a poet, for I have no words (and I don't want to risk posting spoilers).
I will say this though, I love how this series doesn't bother giving you any obvious buildup to its big reveals but instead slaps you across the face with them before you can realize where all the subtle clues are leading you to, and only then does it proceed to explain the logic behind the conclusion immediately afterwards. It's a complete inverse of how such reveals are usually handled, especially in manga and anime.