So.... I don't know if this qualifies, and it's a weird AU born out of a crack RP premise in a fandom far away. But when you say id fic, this is the one that comes to mind for me; partly because I played this character (Kakashi) in the RP, and she had a penchant for solving problems with murderous violence, and that took me by surprise, sometimes. As if it was letting that part of my reptile brain out to play.

Story In Girly, Violent, Mango Sort of Way</a.