LOOK, UP in the sky. It's a bird! It's a plane.

No! It's . . . 

Stuporman?

Otherwise known as Hancock, a superhero who doesn't want to get out of bed in the morning, and as high-concepts go, this one has potential.

Especially with high-achieving, image-conscious Will Smith cast amusingly against type as the surly Hancock, a guy in slacker garb who doesn't show up in the nick of time. He shows up late, with liquor on his breath, and generally has a low opinion of the people he rescues (as well as the people he doesn't).

Will Smith is probably Hollywood's most agreeable actor, and that's key, because the audience needs to live with the antisocial Hancock for a good long while before he agrees to a makeover (parents beware, he's also foul-mouthed, and the movie pushes its PG-13 rating).

In a funny wrinkle, Hancock saves the life of a public relations guy (Jason Bateman) who returns the favor by giving Hancock, resented by greater Los Angeles, an overdue image overhaul (Hancock has been read as a tarnished America, in need of re-branding).

Ray Embrey, the always talking, always pitching, softly sarcastic PR guy, is right in Bateman's sweet spot, and his chemistry with Smith - unshakable optimist and grouch - is very good. Sample: Ray reminds Hancock to always congratulate police during a rescue, and forces him to mouth the words "good job." Smith chokes on the phrase, and gets a big laugh.

There's something resonant and familiar about this relationship, too. The movie obviously satirizes superhero mythology, but it's also easy to compare Ray and Hancock to modern-day athlete and agent. In fact, the movie's first half may remind you, as it did me, of "Jerry Maguire," and Jerry's efforts to turn the aggrieved Rod Tidwell into a crowd-pleasing marketable commodity.

"Hancock," alas, has no interest in being a takeoff or update of "Jerry Maguire" or any movie with such a large dollop of sentiment. As you've probably heard, "Hancock" takes a very sharp turn at midpoint toward gory tragedy, a wild change in tone that director Peter Berg can't control.

Berg tries to foreshadow things - we see Charlize Theron, as Ray's wife, shooting Very Significant looks at Hancock and making cryptic remarks that bespeak special knowledge about Hancock's unusual skill set, perhaps his blank past.

The movie goes on to answer questions about Hancock's history, but not the question many viewers will ask: Why would you turn a successful comedy, no small achievement, into a bloodletting, garnished with the usual F/X overkill?

There are graphic beatings, shootings, and torture sequences, and there are superbeings summoning tornadoes and other wrath-of-God type apparitions that will amaze anyone who hasn't seen, oh, any of the "X-Men" or "Harry Potter" movies.

The strain of sadism that's crept into mainstream American movies eventually overtakes and undercuts "Hancock," which should embarrass the filmmakers, who pay lip service here to gooey idealism.

As he remakes Hancock, the idealistic Ray also pursues a pro bono campaign to expand corporate charity, encouraging big business to earn and use a symbol that proves they have "heart."

Hollywood would be a good place to start. *

Produced by Akiva Goldsman, Michael Mann, Will Smith, James Lassiter, directed by Peter Berg, written by Vy Vincent Ngo, Vince Gilligan, music by John Powell, distributed by Sony Pictures.