It's also a love story. Starla (Elizabeth Banks) is devoted to her husband, Grant (Michael Rooker), and struggles to remain so as he mutates into something freakier and freakier. In what can be construed as an act of mercy, he opts to impregnate Brenda (Brenda James) down the street instead of Starla in order to further his invasion.
And poor, poor Brenda... she begins to swell up something fierce, and by the time Starla and sheriff Bill (Nathan Fillion) find her in a backwoods barn, well, she's a little worse for wear -- as massive as she is above and constantly, ravenously hungry in order to feed her progeny. Alas, Brenda's sides soon split and out spill countless alien slugs looking to take over the tiny town. Ah, the miracle of birth, born out of a Fate Worse Than Death!