Pretty Little Liars has no shortage of villains lurking in the shadows, but it's likely that few people expected one of these villains would share Jessica DiLaurentis' face. The Season 6 finale of Pretty Little Liars dropped a huge bomb about who we should be afraid of, and that person is none other than Mary Drake, Jessica DiLaurentis' identical twin and Charlotte's secret biological mother. Mary posed as the ghost of Jessica to Ali, and I'm thinking it may not be the first time that Mary has pulled the bait and switch on the people of Rosewood. Mary, a former Radley patient, may have been pretending to be Jessica for a long time — especially during Jessica's "trips" to Radley. Could Mary have had the affair with Bethany Young's dad, and pretended to be Jessica? This is one insane twist that would make a surprising amount of sense.
During Charlotte's Big A confession, we learned that Bethany was angry at Jessica because she had just found out that Jessica was having an affair with her father. This came after the Liars learned that Bethany and Jessica had seemingly spent some time together on a horse farm, outside of Radley. It seemed that Jessica was trying to win Bethany over because she was having an affair with Bethany's father, but what if that wasn't the case at all? What if, the entire time, Mary was posing as Jessica in order to seduce Bethany's father? Though it seems unbelievably cruel, the reason that Mary would want to do this actually makes perfect, twisted sense.
In her Big A confession, Charlotte revealed that it was Bethany who pushed Toby's mother Marion off of the roof and blamed it on Charlotte. That led to Charlotte being locked up in Radley and doped up with excessive medication — meds that, according to Charlotte, put her in a catatonic state and nearly killed her. Perhaps Mary saw this and wanted Bethany to pay for putting Charlotte in that situation, deciding that the best way to do so was by messing with Bethany's head. Mary could have posed as Jessica and began an affair with Bethany's father, something she know would drive Bethany crazy.
I certainly wouldn't put it past a family member of the DiLaurentis' to pull such a stunt, and it would make a lot of sense considering that we never really got an answer about Jessica's affair with Bethany's father. Perhaps the truth was, there was no affair — and that this was a trick of Jessica's (even more) manipulative sister. Mary is the mother of Big A, after all — Charlotte had to learn her tricks from someone.
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