My heart sank as I read the Sling Blade press screening notice: “The film is a Southern gothic tale about a man named Karl, who’s just been released from an asylum 25 years after committing a gruesome crime.” 134 minutes of Arkansas-fried Jason? The forbidding prospect made me wish I hadn’t balked at reviewing Beverly Hills Ninja.

When it comes to movies, it’s dangerous to make assumptions. Actor-screenwriter Billy Bob Thornton’s directorial debut turns out to be a mesmerizing oddity, by turns darkly comic and touching, and filled with unexpected, sometimes shocking, twists. Admirers of such writers as Flannery O’Connor, Charles Portis, and James Wilcox, and moviegoers weary of predigested, demographics-driven screen fare, should not let this one get away.

Brilliantly executing the juicy role he devised for himself, Thornton plays Karl Childers, a middle-aged, mildly retarded, poor white Southerner. Committed to an institution for the criminally insane—in his boyhood, he surprised his mother having sex with the town bully and, in a burst of moral outrage, nearly decapitated them using the titular weapon—he has completed his quarter-century sentence and, assured by doctors that he has recovered, reluctantly returns to society.

Back in his cabbage-patch hometown, Karl finds work as a farm equipment repairman and is befriended by Frank Wheatley (Lucas Black), a boy living with his mother Linda (Natalie Canerday) in the shadow of his father’s suicide. Unaware of Karl’s past, they open their home and hearts to the lumbering outcast. But young Frank’s well-being is threatened by his mother’s boyfriend, Doyle Hargraves (country singer Dwight Yoakam), an abusive, alcoholic construction worker who, during violent mood swings, terrorizes mother and son. Timid Vaughan Cunningham (John Ritter), Linda’s boss (at the local dollar store) and soulmate, does what he can to comfort her, but as a gay man marooned in the Bible Belt he also attracts Doyle’s enmity. In an attempt to protect Frank, whom he loves more than anyone he has ever known, and dispel the ghosts of his haunted past, Karl makes a sacrifice that terminates his new-found freedom.

The protracted opening shot—in the hospital, a fellow inmate (J.T. Walsh) slowly drags a chair over to Karl, sits down, and launches a monologue about his pathological sexual exploits—establishes the film’s pace. Leisurely unfolding, Sling Blade takes its rhythms from its protagonist’s sluggish, meticulous thought processes. Initially, the tempo is taxing—one wants to goose the story along—but as we come to know Karl, who despite his history is the gentlest of creatures, Thornton’s direction feels exactly suited to the world and characters of his narrative.

I doubt that any actor could rival Thornton’s performance as Karl. All of its specifics—the hunched-over stance, the high-hitched pants, the compulsive hand-rubbing, the downcast head and fear of making eye-contact, the monotone delivery punctuated by a droning “uh-um” at the end of each line—make this exterminating angel a fully realized character. In a climate where the likes of Tom Cruise and Woody Harrelson receive plaudits for their presumed thespian abilities, it’s difficult to find language worthy of Thornton’s accomplishment here.

The rest of the ensemble, down to the smallest roles, is similarly inspired. Sincere and unaffected, the young, Alabama-born Black is superb in his duologues with Thornton. A plump effigy of his erstwhile TV sitcom heartthrob persona, Ritter, whose Eraserhead haircut makes him resemble a benevolent radish, launches a new career as a character actor, investing the loyal, fearful Vaughan with humor and pathos. Yoakam is alternately scary and funny as an intolerant, macho lowbrow who “can’t stand antique furniture and midgets,” finds the Bible impenetrable, and regards Linda’s friends as “cocksuckers and retards.” Canerday is piercingly direct as his lover/victim—aware of Doyle’s destructive potential, but too lonely and needy to sever her ties to him. Some familiar faces pop up in tiny roles. Director Jim Jarmusch has a wry bit as a frozen-custard drive-in clerk. And in a distracting cameo, Robert Duvall plays Karl’s father. Presumably, his one-scene appearance is a supportive gesture to Thornton, who co-scripted the actor’s recent feature A Family Thing, but because Duvall looks at least a decade younger than his “son,” the sequence is rather bewildering.

For more than a decade, Thornton has been refining his talents in several capacities. With childhood friend Tom Epperson, he wrote the screenplay for Carl Franklin’s 1992 breakthrough independent feature, One False Move (in which Thornton also played a drug-dealing murderer), and has acted in theatrical films (Jarmusch’s Dead Man, Tombstone, Indecent Proposal) and television series (Evening Shade, Hearts Afire). Arguably, his screenplay for Sling Blade is even more impressive than his performance. The tone of his writing has the same seriocomic complexity one finds in the best Southern fiction, a blend of askew wit, compassion, and bleak fatalism. An uproarious dinner party featuring the four main characters and two guests—Vaughan’s lover and Karl’s “date” Marsha (Linda’s plump, slow-witted co-worker)—is filled with excruciatingly droll, deadpan dialogue. (Marsha modestly shrugs off her dollar-store employee-of-the-month citation, explaining, “When you like pricing items as much as I do, it’s just a matter of time.”) This vein of humor enriches a film that might otherwise seem excessively grim. Karl’s account of the grisly fate of his baby brother strikes a note of unexpected horror, while explaining the intensity of his attachment to Frank. The range of emotions Thornton evokes in Sling Blade makes watching it consistently challenging.

In the past few decades, the mentally impaired holy innocent has become a stock protagonist in art films and commercial movies. (The Mystery of Kaspar Hauser, One Flew Over the Cuckoo’s Nest, Rain Man, Forrest Gump, and Shine are the first examples that come to mind.) Just as it would seem time to retire this sentimentalized figure—and ponder why the cinematic representation of goodness has become so closely allied with insanity—Swing Blade appears to renovate this contemporary cliché. I won’t emulate my much-quoted namesake and end with a gassily absurd endorsement (“one of the best films of this year, any year”), but feel confident you’ll find Sling Blade as rewarding as I did.CP