In a monster movie, you have to root for whatever has a face. The face you carry out of Spider-Man 3--which features a couple of monsters--belongs to Thomas Haden Church. His Flint Marko is an escaped convict who falls into a particle accelerator and becomes an animated sand heap. He can rise to the size of a small mountain or turn his fist into concrete sledgehammers, and the tabloids call him Sandman.

Wherever he goes, Marko is always trying to warn people not to get in his way or they'll get hurt. And in his ever-dissolving hand he carries a locket with the picture of his sick child, whom he's trying to help with the loot from the robberies he commits. These Spider-Man movies used to be proof that you could make a CGI spectacle and not lose the sense of structure; Church is all the structure this movie has, and he keeps going missing.

Spider-Man himself undergoes a transformation; as in Superman III, the superhero turns bad. A bloblike piece of extraterrestrial matter slithers aboard Peter Parker (Tobey Maguire) and makes him vengeful and arrogant; it grows on him and turns his suit black. Where Superman got drunk and flicked peanuts against a bar mirror at supersonic speed, Parker turns bad the way a dweeb might--he combs his hair forward and macks on the girls coming down the street. He flips his hips and rolls his package at them and shows up his poor long-suffering girlfriend, MJ (Kirsten Dunst), with a new girl, Gwen (Bryce Dallas Howard).

All the regulars come back for their usual bits. Director Sam Raimi, a Three Stooges fan, restages a vintage Moe Howard routine with J. K. Simmons as J. Jonah Jameson. This time "America's most respected newspaper editor" is nursing his blood pressure with a trayful of pharmaceuticals. Rosemary Harris, looking more spry than in the last outing, returns as Aunt May to set Peter on the moral railing off of which he keeps jumping. Discovering that Sandman was the triggerman in the death of Uncle Ben, Peter is swept by vengeance. And 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 he considered breaking this film into two movies, and this rambling story is forced into one but 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. Topher Grace plays Eddie Brock, a glad-handing plagiarist photographer who picks up Peter's alien parasite. Where Peter is a benign spider, Venom is more like a tarantula. He has no aim more ambitious than to kill Spider-Man. There's rarely a good way to link up a conspiracy of supervillains, but the scene of the Sandman and Venom meeting in an alley is the worst planned of anything in these three movies.

Spider-Man 3 is an anxious film. It tries to top the other two by tripling up the villains, instead of giving us a new facet of Parker. Rather than becoming arrogant and silly, wouldn't it have made more sense if Parker became a muttering obsessive, brooding over the police scanner?

Spider-Man 3 has heart, yes, but its head is spinning, a sequel deeply confused and finally unnecessary. The climax is a tag-team wrestling match between costumed heroes and villains, with a public cheering on the violence. And here, Church's solemn grief dissolves; the Sandman turns from a tragic fugitive to faceless flying debris, an image of that sandstorm that still traps our soldiers.

'Spider-Man 3' opens everywhere on Friday, May 4.

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