Secret identity crisis

We all know Tobey Maguire spends a lot of time in the ‘‘Spider-Man’’ movies on his best behavior. But for one comical stretch in ‘‘Spider-Man 3’’ (which, to the relief of zillions, opens everywhere tomorrow night at 11:59), Maguire wilds out. The explanation is a long one. But basically, an inky substance from outer space follows Peter Parker home, invades his Spider-Man uniform, and introduces him to the ample thrills of being bad — as bad as somebody who suddenly looks like he fell in with Fall Out Boy can be.

Peter wears this new black suit beneath his street clothes like an undershirt. Soon his jeans get a little tighter, his patience a little thinner, and his hair long enough to flip in hilariously cocky irritation. He struts down the streets of Manhattan in a dual state of geeky entitlement and Travoltan bliss while some lite disco-funk plays around him — he’s got night fever. The ladies who stop to check him out aren’t turned on. But he’s impressed himself. It’s as if, over night, Peter has gone from lowly bio-chemistry student to biotech jerk. Don’t worry. It’s a phase.

Under the playful yet perceptive direction of Sam Raimi, ‘‘Spider-Man’’ has always been about its characters’ psychological and emotional tribulations. But this sequence feels fresh because it’s a real release. The rest of ‘‘Spider-Man 3’’ is an intricately plotted saga which takes our hero from adolescence to adulthood. After six years, the franchise may be familiar, and lucrative, yet it hasn’t curdled into a burdensome series of ones, zeroes, and dollar signs.

This time, the villains — including Thomas Haden Church as Sandman — aren’t villainous so much as misunderstood pains in the neck. Dark forces spring from the central characters’ self-doubt, and life-size insecurities from human personality crises.

In the opening minutes, Peter and his girlfriend, Mary Jane (Kirsten Dunst), are ecstatically in love when we catch up with them. By the end the previous movie, he had come out to her as Spider-Man, and now her stage career has taken off.

After the opening night of her new musical, they lie in a deluxe web and stargaze in a park. The sight of Maguire and Dunst, who’s as radiant and vulnerable as ever, suspended like that, making out, is a wonderful image: simultaneously innocent, weird, and erotic. Then in the background a glowing meteor blazes softly to earth, and that black blob oozes out. Peter and Mary Jane are gleefully oblivious, driving off on his motorbike, as the goop affixes itself to the fender.

This could well be the opening scene from a 1950s B horror flick, and points to a gleeful hook of the ‘‘Spider-Man’’ series: The coolest thing about these movies is how uncool they are. Raimi gives us Eisenhower-era squareness that blooms in a technologically state-of-the-art New York. ‘‘Spider-Man’’ exists out of time, so the walk, say, from Natalie Wood to Kirsten Dunst is very short.

SPIDEY-MANIA

See photo galleries, trailers, and more on ‘‘Spider-Man 3’’ at boston.com/films.

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In any case, Peter and MJ, as he calls Mary Jane, don’t have equilibrium for long. She wants a little humility, but he loves that New York loves Spider-Man. Right before he can ask her to marry him, she walks out in frustration. On the bright side, she finally seems to have a found a flattering hair color.

Meanwhile, Peter and Harry (James Franco), who, when we meet him, is still seething at Peter/Spider-Man for killing his father, the Green Goblin, achieve an accidental rapprochement. A show-stopping fight between them in the first 20 minutes leaves Harry with a memory-erasing concussion that temporarily reboots their friendship. When Harry gets home from the hospital, he and Peter share some boyish horseplay around his penthouse. It’s a gentle, affectionate contrast to their near-murderous brawl a few days before.

Maguire and Franco still seem to be enjoying themselves after all these years. You really miss Franco’s easy-going nature when he’s gone for too long. But the editing is so smartly paced that the second you want to see him, there he is.

The script keeps Maguire on the move, but part of the reason this movie sails along with such deceptive effortlessness is that he keeps finding energetic new gears to play this character. Peter began as an affable nerd whose powers shocked him. Then he became a cauldron of emo disaffection, wanting love but too meek and selfish to declare himself. Now he’s on the cusp of adulthood, struggling to balance his emerging self-confidence, his intense affection for MJ, and the exhaustion of working two jobs that still keep him living in a dumpy apartment. (Crime may not pay, but from the looks of it neither does stopping it.) He keeps a police scanner beside his bed and has to face the possibility that Sandman may have killed his Uncle Ben. Throughout, Maguire makes it all look like the easiest acting he’s ever done.

Raimi, who shares script credit with his brother Ivan and Alvin Sargent, strikes an exquisite balance between pop and woe, drama and whooshing adventure. The series has the shadows and demons of Tim Burton’s two ‘‘Batman’’ films, but the sensibility is very comic book. Bill Nunn, Elizabeth Banks, and the rousing J.K. Simmons, as the implacable editor J. Jonah Jameson, resume their roles at the Daily Bugle where Peter works as a freelance photographer, giving the film a screwball zing.

This time Peter finds himself competing with an arrogant new hotshot, Eddie Brock (played by Topher Grace), whom Jameson will grant a staff job should he find incriminating photos of Spider-Man. With the new black suit — which, for Peter, becomes a freeing id — catching naughty Spidey could get easier.

This, by the way, is a movie of intense replacement and doubling. Grace is Maguire’s lankier, more sardonic doppelganger. Like Peter, Harry discovers another self. Even Mary Jane gets an opposite number in Gwen Stacy (Bryce Dallas Howard), a blond model whom Bad Peter starts seeing.

Describing ‘‘Spider-Man 3’’ as busy is an understatement. It sets out to accomplish a lot, maybe too much: The film lasts well over two hours, and toward the climactic fight sequence fatigue starts to set in.

To their credit, though, Raimi and his big, hard-working crew are determined to dazzle (the budget is rumored to be almost $300 million), even at the risk of bombarding us with pleasure, people, images, action, and real feeling. The movie has the curious effect of leaving you over-fulfilled. When it’s done, any appetite for another event picture, even one half as well made as this, is temporarily curbed.

Don’t get me wrong. Blockbusters with this much going on should come along more often. But they should also come with a doggie bag.

Wesley Morris can be reached at wmorris@globe.com. For more on movies, go to boston.com/ae/movies/blog.