After including in its first season's finale death, dismemberment, a double wedding and Delta Burke, Popular no longer boasts an overstocked arsenal. So, for its sophomore-year showstopper (airing May 18 at 9 pm/ET), the WB's schizophrenic high-school dramedy is unleashing its secret weapon: Tammy Lynn Michaels as Nicole Julian, the megabitch with the cruelest intentions since Winona Ryder's Heathers clique.

"In this episode, Nicole's behavior will make the rest of her actions seem angelic," the actress promises TV Guide Online. "It's out of control. At the table reading, we usually get through the scripts guffawing. This time, all you could hear was, 'Oh my God! Oh my God!'"

Alas, Popular may not merely be ending the semester with a bang; as the WB has yet to register the series for the fall, it could also be winding up its entire run — a possibility on which Michaels prefers not to dwell. "Everyone's remaining tightlipped," she sighs, acknowledging that ratings dipped briefly when the show traded its wild and crazy plots for Sturm und Drang. "With Buffy the Vampire Slayer leaving, and the [threat of writer and actor] strikes, I don't think anybody knows anything."

Whether the network determines that Popular lives up to its title, the Indiana native won't change how she spends her summer vacation. "There's a possible movie," reveals the ambitious starlet, who — despite her insistence that she resembles her ruthless TV character only, ahem, once a month — backs up her punchlines with killer instincts. "It may not happen, though, in which case I will put out a hit on the girl that gets the part.

"I'm just kidding," she adds quickly. "Don't print that."