[TOMT] [SHORT STORY] [2000s] Short spooky story about girl who kills loved ones who get swapped out for monsters
Hi all, I'm looking for a short story that I remember reading in the 2000s. I think it was in one of those horror anthology books, but perhaps a lesser known one (it wasn't "Scary Stories to Tell in the Dark"). It was about a girl who realized her parents had been swapped out for monsters—subtle ones, apparently—who were basically just gaslighting her and being really mean. She had to kill them of course. Now she's in college, and she realizes it's happening again, this time in the form of her roommate. She feels sorta bad killing her, musing on the real girl she was before the monster took over, but ultimately feels justified for this and the murder of her parents. She says she's like a "scapegoat" in the old timey sense, kind of a christlike figure, taking the world's evil upon herself so we don't have to. "Scapegoat" may have been the title of the story. Any ideas?