Credit: Hulu

Everyone has been wondering who the Black Swan was during Pretty Little Liars Season 2, Episode 25: “UnmAsked,” but many observant fans also noticed a woman in a bright red dress and gold mask at the ball.

Red — the color of Alison's (Sasha Pieterse) Vivian Darkbloom coat — has become a thematically important to Pretty Little Liars, and this woman's entrance to the ball, though not noted by the Liars, was clearly meant to be noticed and remembered by fans, based on how much visual importance it was given on screen.

So, who is she? She has long blond hair (though that could be a wig), a statuesque figure, and likes to creep around in the background. Well, that doesn't really help narrow it down, does it? Still, here are a few of our theories about who this mysterious woman could be:

Alison: Honestly, we're not going to be 100 percent sure Alison (Sasha Pieterse) is really dead until the very last episode of this show airs and she hasn't come back. We think it would be an intriguing twist, and apparently a lot of our readers agree it's possible. Aliso would totally lurk around a ball for funzies, and she is a blonde.

Alison's twin: Hey, she had one in the books, she could have one on the show, too!

Kate: The woman in red kind of looks like Hanna's (Ashley Benson) evil step sister. But why would Kate be given such an important place in the shot? Unless maybe she's up to more than just random mischief...

And, of course, the question remains: Is this person in red related to "A" in some way? The person who came to talk to Mona (Janel Parrish) at the end of the episode was also wearing red. Is that a sign that they're the same person, or somehow connected? Perhaps...

What do you make of this mysterious figure? Weigh in at our Facebook page.

Catch an all-new Pretty Little Liars when Season 3 premieres on Tuesday, June 5 at 8 p.m. ET/PT on ABC Family.