SLITHER If nothing else, this deserves credit for offering us a break from the current trend of nihilistic horror flicks whose sole purpose is to devise groovy new ways for psychopaths to torture and murder innocent people. Make no mistake: Slither offers gore by the bucketful, but the movie’s in the spirit of those enjoyable, us-against-them monster yarns that ran rampant from the 50s straight through to the mid-80s. Starting out as an “invader from outer space” opus (think The Blob) before switching gears to become a quasi-zombie flick (think Night of the Living Dead), the film involves a gelatinous E.T. that turns hicksville businessman Grant Grant (Michael Rooker) into its agent of evil on earth. The master plan eventually involves a mass assault by hundreds of slugs that take over humans’ bodies by entering through the mouths; naturally, the entire planet is doomed unless double-Grant’s wife (Elizabeth Banks) and an amiable sheriff (Nathan Fillion) can figure out a way to shut the otherworldly operation down. Slither takes its time getting started, but once it does, it never lets up, throwing the blood, slime and one-liners (some woeful, most of them witty) at the screen with feverish abandon. Banks, recently seen as the bookstore nymph in The 40-Year-Old Virgin, is actually touching as the wife who doesn’t comprehend why her husband has morphed into a human squid. And between his starring roles here and in last year’s sci-fi tale Serenity, Fillion might end up becoming a new generation’s Bruce Campbell. The worst part of the film is the unnecessary coda tacked on after the closing credits have run their course; luckily, the auditorium will be empty at that point anyway.