It looks like we have an Alison DiLaurentis 2.0 on our hands. Obviously this is a second-rate version, but this girl is trouble and she has it out for Emily Fields. Who is Addison Derringer on Pretty Little Liars? Aside from being Ali reincarnated, she is also a student in her English class and a member of the Rosewood High School swim team.
I have no idea why Addison has such an attitude, but she seriously has it out for Emily. She went out of her way to eavesdrop on her private conversation with Ali, took pictures of them close to each other mid-conversation, and she even told Paige McCullers that Emily was hitting on her — which she obviously wasn't.
I don't know what her deal is, but I also find it pretty suspicious that she happens to be rocking those A.D. initials. I doubt that she's the big bad villain we've all been waiting for. It would just be so anticlimactic for a high school girl that no one knows to be terrorizing the squad. Nevertheless, she's obviously a major problem.
We don't know much more about Addison so far other than the fact that she's a high school bully who thinks that she is way cooler than she actually is. Addison might think she's running things, but I have a feeling that the old Alison is going to resurrect and completely own the wannabe eventually.