Biggest Piece of Evidence: The show's creator, I. Marlene King, already revealed there's a new "big bad" to worry about, and it's Uber A. This might be the first move in the biggest game of them all.
The Point of Contention: There were hints of the return of Uber A, of course, but nothing concrete enough for us to know for sure. And we're pretty sure Uber A plans to make themselves known.