As you probably know by now, tonight's episode of Pretty Little Liars, Season 3, Episode 5: "That Girl is Poison," revolves around a big birthday bash for none other than Jenna Marshall (Tammin Sursok). But what can we expect at the first party of the season? Showrunner Marlene King dropped a few clues. Read spoilers at your own risk! For more on Wetpaint Entertainment's philosophy on spoilers, click here.