IN A MONSTER MOVIE, you root for whatever has a face. The face you carry out of Spider-Man 3—which boasts a couple of monsters—belongs to Thomas Haden Church. He plays Flint Marko, an escaped convict who falls into a particle accelerator and becomes a sentient sand heap. He can rise to the size of a small mountain or turn his fist into concrete sledgehammers; the tabloids call him Sandman. In a movie where no one seems to know where he's going, Marko is always pursued—chased by bloodhounds before his transformation, hunted by Spider-Man (Tobey Maguire) afterward. Wherever he goes, he is always trying to warn people not to get in his way or they'll get hurt. And in his dissolving hand, he carries a locket with the picture of his sick child whom he's trying to help with the loot from his robberies.

The Spider-Man movies used to be proof that you could make a CGI spectacle and not lose the sense of structure, Church—as much a sad, noble fugitive as a villain—is all the structure this movie has. And he keeps going missing. As in Superman 3, our superhero curdles. A piece of extraterrestrial tar slithers aboard Peter Parker and turns him vengeful and arrogant. Where Superman got drunk and flicked peanuts against a bar mirror at supersonic speed, Parker turns bad the way a dweeb might—he slicks his hair forward and macks on the girls. And he shows up long-suffering girlfriend M.J. (Kirsten Dunst) with a new escort, Gwen (the inert Bryce Dallas Howard). Discovering that the Sandman was the triggerman in the death of Uncle Ben, Peter is swept by vengeance. So is Harry Osborne Jr. (James Franco), heir to the armory of the Green Goblin. He goes flying, and pretty soon the mixed metaphors do, too, as Spider-Man tries to learn not to be bent by revenge while carrying out the vigilante's trade.

Raimi has claimed that he considered breaking this film into two movies, but this rambling story is forced into one—and still looks like two. The most extraneous part of the script is an evil man-spider called Venom, a creature who has all of Spidey's powers, in addition to fangs and claws. Spider-Man 3 is an anxious, confused film. It tries to top the other two by tripling up the villains, instead of checking a new facet of Parker. The Spider-Man movies were part of what happened to America after Sept. 11. This was true even from the beginning, when an advertising teaser of a web strung between the Twin Towers had to be scrubbed after the attack.

At the risk of being like a schoolmarm's lecture, these movies insisted on the responsibility of power and the nihilism of seeking revenge. Should I explain why that insistence made these films such an urgent fairy tale for America? But this sequel is as unnecessary as it is confused. The climax is a tag-team wrestling match between costumed heroes and villains, with New Yorkers cheering on the violence as the buildings crumble around them. And here, Church's solemn grief dissolves. The Sandman turns from a tragic victim of circumstances to faceless flying debris, becomes an image of that sandstorm that still traps our soldiers.

Spider-Man 3 (PG-13; 140 min.), directed by Sam Raimi, written by Ivan Raimi, Alvin Sargent, Stan Lee and Steve Ditko, photographed by Bill Pope and starring Tobey Maguire and Kirsten Dunst, opens May 4 everywhere.

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