Warning: huge, massive, GIGANTIC spoilers ahead for the Pretty Little Liars series finale.
If Pretty Little Liars is known for one thing after seven seasons, it has to be the way it serves up absolutely wild plot twists are so outlandish that no lesser show would dare try to pull them off. This is a show that lasted even beyond the resolution of the central mystery, going on even after the identity of A was revealed. Hanna, Emily, Spencer, Aria, and Alison found plenty of new mysteries plaguing their lives as the years passed.
The latest mysterious villain to mess with the girls was none other than "A.D." Showrunner I. Marlene King made us wait until the very last episodes of the very last season to find out the identity of the person behind the initials, and it was a shocker. A.D. is none other than Alex Drake, a.k.a. Spencer's evil twin.
Okay, yes, A.D. as Spencer's evil twin has been speculated by some fans, and Pretty Little Liars is probably the only show that could possibly get away with playing the reveal of an evil twin totally straight, but it still came as a big surprise when Alex popped up with a British accent and a vendetta to take Spencer's vastly superior life for herself. She wanted Spencer's friends and family and lifestyle; naturally, as you do, Alex took extreme steps to make herself look like her long lost twin and insert herself into Spencer's world.
In what is arguably the creepiest twist of the finale, we had it confirmed that Spencer wasn't always Spencer in her Season 7 scenes. Sometimes, when we thought we were watching Spencer, we were really watching Alex doing her best Spencer impression. I. Marlene King has come out and revealed how long Alex was impersonating Spencer in the events of the series, saying this:
Something tells me Toby might be inclined to quiz Spencer before any future hookups until A.D. becomes nothing more than a distant memory. In fact, I wouldn't blame any of the characters if they started exchanging secret code words just on the off-chance that they had an evil doppelganger out there. As it turns out, actress Troian Bellisario was working to build Alex's character for a while, even if we didn't catch it at the time. I. Marlene King went on in her chat with The New York Times to say this about what Bellisario brought to Alex as opposed to Spencer:
Luckily, none of the characters have to worry about Alex coming back to haunt them any time soon. The second-to-last scene revealed that Mona had Alex and Mary King dressed up and living in her twisted version of a life-sized dollhouse in Paris. It's a pretty unsettling fate for an unsettling character, and oddly fitting. For once, the girls all had a happy ending, and their villain was nowhere to be seen with no prospects for escape. Sure, another group of teenage girls in Rosewood seems in for a rough ride with a mystery of their own, but Hanna, Emily, Spencer, Aria, and Alison really might get their happily-ever-afters following seven often hellish seasons.