It's hard to believe, but Pretty Little Liars has been around for four and a half seasons. That's a whole lot of mystery, drama, and catty behavior to keep track of, so every week on Flashback Friday we like to look back at a memorable moment from seasons past.

Since yesterday was Halloween and we all have Alison DiLaurentis (Sasha Pieterse) on the mind, what with her being alive and all, today we're revisiting a key scene from the very first Halloween episode, Season 2, Episode 13: "The First Secret."

In this scene Alison and Jenna have a Lady Gaga costume face-off. If you recall, the two girls had met once before, and Ali had told Jenna to drop her costume idea because Gaga was all Ali's. Jenna, not so easily cowed, showed up in her original costume anyway.

In this clip Ali does her best to take control of the situation, offering Jenna her friendship — with the subtle implication that Jenna would become one of her minions, like everyone else. Jenna says thanks, but no thanks.

Oh, and that's not all: At the end, Mona cozies up to Jenna, claiming that Ali "doesn't scare me." Is that the beginning of a partnership that goes far deeper than we've ever supposed?

Re-watch the scene below, and then let us know what you think it all means in the comments.

Catch the Pretty Little Liars Season 4 winter premiere on Tuesday, January 7, 2013 at 8 p.m. ET/PT 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+!