“It’s fantastic!” Says the fallen man to the means of his ruination. “You look like that, you screw like a bunny and you have no soul! Seriously. It is awe-inspiring.” Yeah, it is. He’s speaking to Clea, a 22-year-old faux-naive succubus busily fucking her way up the ladder of the New York TV business. She’s the greatest creation of Theresa Rebeck, a playwright I had previously considered more fun than frighteningly talented, and she burns a horrid swath across the lives of everyone else she encounters in this savage show-biz comedy. In Portland Playhouse’s production, directed by Tamara Fisch, Leif Norby, Ty Hewitt and Laura Faye-Smith are all turn in strong performances, but Nikki Weaver’s Clea commands the stage, seeming to absorb all the light in the room. Her speech is a high-velocity mess of misused adjectives, her inflection an abominable mating of Valley girl and Ira Glass, and she moves with a calculated looseness that hold the gaze even as her personality repulses. Aging actor Charlie (Leif Norby) is especially repelled, but winds up drawn in anyway, sabotaging his career and successful marriage  to a competent, affectionate professional in a nightmarish tryst. It isn’t really Clea’s fault, of course. Rebeck has a keen insight into why happily married men self-destruct—it’s all about power and pride—and a creature like Clea can only facilitate the disaster. But still—wow, is she awful, claiming not to drink while guzzling vodka, constantly expressing dismay at the negativity of others while flinging insults of her own, jerking her body to wherever it may best be displayed. Weaver’s is the most demanding performance I’ve seen this season; you cannot look away, no matter how much you might like to run screaming from the theater.

GO: The Scene at Portland Playhouse, 602 NE Prescott St., portlandplayhouse.org. 8 pm Thursdays-Saturdays, 2 pm Sundays. Closes March 13. $16-$21.