For about 30 minutes, "Hancock" is the perfect antidote to the glut of superhero movies that have filled theaters this summer -- a biting satire with Will Smith at his best, playing a drunken, destructive superhero who's more hated than beloved.

But then the movie takes a hard turn that pulls it back into the genre and the fun disappears, replaced by sappy, dull nonsense.

That veer to the inexplicable and conventional makes "Hancock" one of the biggest disappointments of the summer movie season.

But because it's Smith and the Fourth of July, "Hancock" is a sure-fire hit, likely headed for the $100 million range its first weekend, providing further evidence that box office success has nothing to do with a picture's quality.

Smith plays Hancock, a downand-out Los Angeles superhero who we first see passed out on a bus stop bench. Rousted by a kid, he grabs
a bottle and goes airborne to put an end to a police chase of an SUV loaded with bad guys with machine guns.

Flying through birds and sending feathers flying, then careening drunkenly into the car, Hancock tortures the bad guys like a cat with a mouse before doing millions of dollars in damage by slamming the SUV down on the needle atop the Capitol Records tower.