With his slime-time appetites and don't-bother-me attitude, Shrek, the Grumpy Green Ogre, was the perfect antidote to that eat-your-vegetables cheer of spokesmodel the Jolly Green Giant.

Note that I say "was." As far as the adventures of Shrek go, it grieves me to report that the third time is charmless. Swamp Thing, drafted here to succeed the dying king, is adrift. And his film is becalmed.

Shrek the Third isn't a movie, it's the extension of a brand.

It's hard being Green, especially when your corporation relies on you to make sure its ledgers stay that color and you're making a movie and you're busy rehearsing the Broadway-bound Shrek: The Musical and preparing the holiday special, Shrek the Halls. No wonder the ogre frowns at the idea of wearing the crown. Too little time.

What's even worse about Shrek the Third: too few smiles.

The last installment of the Shrek trilogy opens with a comical deathbed scene: As his dying wish, King Harold wants Shrek to succeed him. Evidently, Far Far Away is a family business where the son-in-law is handed the reins, rather than a monarchy where the closest blood relative - paging Princess Fiona - assumes the crown.

The prospect of wearing a corset and hosting state dinners at the castle doesn't appeal to Shrek, whose taste runs to crocheted vests and crockpot meals. The prospect of a Shrekling, which appears imminent, appeals to him even less.

So Shrek does what heroes have done since Odysseus. He goes on a quest, leaving wifey home to defend herself against the man who would be king, Prince Charming.

Shrek (the roguish brogue of Mike Myers), accompanied by his faithful Donkey and Puss in Boots, sets sail to find Fiona's half-brother Artie (voice of Justin Timberlake), geek-princeling at the medieval version of the high school in The OC. Shrek is hoping to crown him King Artie. In a Camelot gag that only adults will get, Artie's tormentor at school is Lancelot.

Where the prior installments of the Shrek saga had a defining plotline, Shrek 3 has three parallel stories, each, it would seem, pitched to a different demographic.

In theory, the one about the geek picked on by jocks appeals to boys, the expectant-father anxiety plays to adults, and the tale of how Fiona and the princesses (Snow White, Cinderella, Sleeping Beauty, Rapunzel) foil a coup in Shrek's absence intrigues girls. The sight of Fiona and her Disney-princess posse morphing into a medieval Charlie's Angels made me almost snicker.

Whatever happened to movies that unify the audience instead of slicing them into pieces of demographic pie? Whatever happened to building a joke that has a payoff instead of punning on a pop-culture phenom?

Visually speaking, the characters in Shrek the Third are colorfully drawn and beautifully detailed, virtues that have the effect of making Shrek, Fiona and gang seem even more monochromatic and generic.