Pretty Little Liars Season 3, Episode 16: "Misery Loves Company" was chock-full of shocking moments, but none were as mystifying as the brief moment where Hanna (Ashley Benson) caught a glimpse of the reflection of a blonde in a red coat, right before she headed into a room full of creepy mannequins.

Who was that apparition? We've come up with a few theories — and we want to know yours!

1. The main "A". A figure in a similar red coat appeared to Mona (Janel Parrish) at the end of Season 2, Episode 25: “UnmAsked,” and Mona seemed to defer to him/her (it seems to be a woman's coat, but who knows?). Many suspect that figure is the one calling the shots on the "A" team. Did that person show up to make sure the attack on Hanna went down as instructed?

2. Alison (or her twin). We know Alison (Sasha Pieterse) once wore a red coat as part of her Vivian Darkbloom persona. Sure, Vivian also came with a black wig, but if Ali is alive, maybe she kept the coat but ditched the hair. Though if she is alive and did appear to both Hanna here and Aria (Lucy Hale) later in the episode, she must have changed, since this figure had black pants, and in the scene with Aria Ali was wearing green pants.

3. Mona in a wig. Maybe the figure was Mona, watching (in disguise) to make sure that Toby followed through with the plan.

4. A different member of the "A" team. For instance, we're still suspicious of good old CeCe (Vanessa Ray), who also has that distinctive blonde hair.

5. Hanna's imagination. We can't rule out that Hanna was imagining things. Maybe she subconsciously realized something was wrong, and this was her brain's way of saying so.

Of course, these theories aren't mutually exclusive, either. (Could Ali be the main "A"? We think so.) 

Who do you think it was? Share your thoughts in the comments below.

Find more Pretty Little Liars spoilers here.

Catch the next episode of Pretty Little Liars on Tuesday, January 29, 2013 at 8 p.m. ET/PT on ABC Family.