Someone was sneaking around Ezra's (Ian Harding) cabin o' mysteries at the end of the Pretty Little Liars Season 4 winter premiere (Season 4, Episode 14, “Who’s in the Box?”) — could it have been Aria (Lucy Hale)?

Pretty Little Liars is a twisty, turny show where the only rule is to expect the unexpected. Each week, we like to dive into the world of fan theories to dig up an out there idea that still, somehow, makes sense. After all, in Rosewood, you never know when the most extreme option will turn out to be the truth.

This week we want to address the tag from the Season 4 winter premiere, which left a lot of fans scratching their heads. The short scene showed someone in black (presumably "A") sneaking into Ezra's cabin, and a lot of fans are questioning exactly who it was. We happen to like the theory this Tumblr user proposes: that it was actually Aria in that scene.

Why? Here are a couple of the reasons this theory intrigues us.

Why would Ezra be sneaking into his own house? As another Tumblr user points out, it seemed like the person in the tag was sneaking into the cabin, which doesn't make sense if it's Ezra. This is the main reason people are coming up with theories about who else it could be.

Aria has a key. As the episode made very clear, Aria was given the key to the cabin. While that will probably come into play next week when, based on the preview, the Liars return to Ezra's cabin it also means she had easy access, so could have been the person in the tag.

Could she be involved in the "A" team? This theory is linked to a broader theory that we've discussed before: That Aria herself could be "A", perhaps as the result of a split personality.

What do you think of this theory — is it possible, or totally crazy? Sound off in the comments below.

Catch the next episode of Pretty Little Liars Season 4 on Tuesday, January 14, 2013 at 8 p.m. ET on ABC Family.

Rebecca Martin is an Associate Editor at Wetpaint Entertainment and our resident Game of Thrones, Breaking Bad, and genre TV expert. Follow her on Twitter and Google+!