Matthew McConaughey has enjoyed a bit of a reinvention over the past year or so, casting aside eager-to-please roles in forgettable romantic comedies for dark, serious work in films with more shading and complexity to them.

This began with 2011’s "The Lincoln Lawyer," in which he played a sleazy lawyer who finds his swagger may not help him get out of every jam. It continued earlier this year with supporting roles as a slick, self-promoting district attorney in "Bernie" and as a stripper-turned-nightclub owner hungry for money and fame in "Magic Mike."

‘KILLER JOE’ Rated: NC-17 Opens today at Consolidated Kahala

But McConaughey’s evolution reaches a thunderous crescendo in "Killer Joe," in which he plays the title character: a meticulously smooth Dallas police detective with a side business as a hit man. He’s calm and controlling, soft-spoken and impeccably dressed. And he’s extremely dangerous.

If you look closely, McConaughey hasn’t changed all that much. All these performances call upon him to play on his persona, to work that seductive charm with his sexy smile and Texas twang, but now he’s doing it for dubious if not deadly purposes. As he embraces his maturity, he’s establishing a much more powerful screen presence.

Joe is the frightening figure at the center of William Friedkin’s pulpy Southwestern noir, full of drug dealers and trailer parks, diner tips and tuna casseroles. This is the second time the veteran director of "The Exorcist" and "The French Connection" has adapted a play from Pulitzer Prize-winner Tracy Letts; their first collaboration was 2007’s "Bug," about a couple who hide in a motel room and feed on each other’s paranoia, with Letts adapting the screenplay both times.

Whereas "Bug" was ridiculous and didn’t know it, "Killer Joe" is ridiculous and absolutely wallows in it. It revels in its low-rent digs and lowlife criminals. These characters are types, people at the fringes of society who are screwed up beyond redemption, but the actors playing them are clearly having a blast slumming.

"Killer Joe" is seriously graphic and squirm-inducing, especially at its climax — there’s a reason it earned an NC-17 rating — but while it may sound crass to enjoy on-screen violence at a time like this, the movie can be hilarious and unexpectedly fun.

It’ll set you on edge from the beginning, though. Chris (Emile Hirsch), a 22-year-old drug dealer, owes his boss $6,000 when his mother steals his stash. Desperate, he goes to his beer-drinking, auto mechanic father, Ansel (Thomas Haden Church), who’s divorced from his mom, to set a plan in motion: They’ll have her killed and collect on her $50,000 life insurance policy.

Killer Joe is just the man for the job. Trouble is, he wants the money in advance. They don’t have the money — but they have something else Joe might want: Chris’ teenage sister, Dottie (Juno Temple), whose revealing wardrobe and provocative demeanor contradict her virginity. Dottie becomes sexual collateral of sorts, which oddly she does not seem to mind; Temple and McConaughey’s scenes seem like all kinds of icky at first, but a strange sweetness eventually emerges.

Also in on the plan is Ansel’s new wife, the trashy waitress Sharla. As you might imagine, Gina Gershon seizes the role with total gusto. She’s formidable but she also isn’t afraid to get a little dirty — or a lot dirty.

There are no lessons here, there’s no hidden message. Friedkin has given us the kind of stylized, violent genre exercise of a man who knows his craft but also has been around long enough not to care what anyone thinks.

Maybe "Killer Joe" approaches the notion that deep down, we enjoy things we may not like to admit. But mostly it’s about the garish spectacle of it all.

Like a deep-fried Twinkie at the State Fair of Texas, "Killer Joe" is gooey, flavorful and bad for you. Dig in.