There's no mistaking Guillermo del Toro's monsters for those hiding under any other bed. In The Devil's Backbone and Hellboy, the Mexican director honed a distinctive species of wraiths—and in Pan's Labyrinth, his latest, best work, the beasties are clawing out of the woodwork. Emaciated humanoids? Check. Bulbous amphibians vomiting slime across the frame? Why, yes. Dudes with ancient hieroglyphs carved on their skin? In spades.

But no fiend haunts del Toro, or terrorizes his audiences, quite like the righteous ideologue. More than any other director, he recognizes the brutality and madness lurking within the true believer. In Pan's Labyrinth, the fascination with fascism continues. Ofelia, the movie's intrepid 12-year-old heroine, is warned that one of the creatures she must confront "is not human." Considering the humans Ofelia has already met in the Spain of 1944, a year when Francisco Franco was squeezing the life out of his people, "not human" is quite the compliment.

Of the specters Ofelia (Ivana Baquero) encounters in the maze behind her country house, none can hold a candle to the man who wants her to call him "Father." Captain Vidal (Sergi LÓpez) is an agent of Franco's nascent dictatorship, deployed to the forest to mop up the last resistance to the GeneralÍsimo. Vidal considers himself an emissary of "a clean, new Spain," but he's not above messy methods. Indeed, he takes a positive relish in the wet work of the pliers and the chisels. He's a sadist in spit-shined boots, a brute impervious to pain or pity—and he's married to Ofelia's mother.

Little wonder that Ofelia is more at ease around enchanted insects and giant toads. Soon after her arrival at Vidal's headquarters, she's summoned for a nocturnal meeting with the local faun—a creature with the head of a goat and the movements of Montgomery Burns. He tells her she is actually a princess of the underworld and assigns her the standard coming-of-age rituals: finding keys, pilfering daggers, sneaking into the banquet hall of the Pale Man. Oh, you know the Pale Man. He's that reptilian chap with the eyeballs in his palms.

That description, of course, does little to convey the apparitions del Toro has cooked up for his fever dream. The title Pan's Labyrinth is something of a mistranslation (this faun is not the Greek deity Pan, but a slightly kinder Catalan cousin), but it's telling all the same: Pan was the god of irrational terrors. In Ofelia's fantasy world and in Franco's country, suffering is doled out with a diabolical logic. If a little girl steals fruit from the Pale Man's table, he will eat her alive. If a captured freedom fighter can't count to three without stuttering, Vidal will torture him to death. And both villains expect history to commend their atrocities. Vidal is obsessed with nurturing an infant son to carry on his legacy, while the Pale Man has commissioned frescoes of his baby-eating exploits.

All this carnage, explicitly rendered, has moved many critics to laud Pan's Labyrinth as the herald of a new maturity in its director. No more with the cartoon Nazis and the mechanical vampires; Pan has taught del Toro to grow up. But this analysis has almost no relation to the actual movie, which is stubbornly childlike in its wonder and unapologetically pulpy in its visuals. The bright colors and broad performances (Lopez's Vidal is the most subtly drawn character, and this is a guy who sews up his own facial wounds) make it feel an awful lot like a comic-book adaptation. It even shares with Hellboy an innocent hero and a preoccupation with occult runes. This is still greasy kid's stuff—if not fit for children.

But this time the grease is corrosive. Del Toro's visual invention is so complete that it's easy to think it has no precursors, but he owes an enormous debt to the 19th-century paintings of Francisco de Goya—images that exemplify the horror of despotism. Watch the introduction of Vidal, as he slaughters innocent rabbit hunters, and you're seeing a re-creation of Goya's masterpiece The Third of May. And that slack, ravenous mouth of the Pale Man? It's the central image of Saturn Devouring His Son.

The influence extends beyond the borrowing of a few choice pictures. Goya and del Toro share a recognition of Spain's catastrophic history, and they both have a profound understanding of the nightmare worlds invented by totalitarianism—worlds that always devour their children. This is never more evident than in the final scenes of Pan's Labyrinth. The twin stories of the movie are not resolved; instead, they diverge toward redemption and despair. Ofelia succeeds in her rite of passage, but a dab of the deep magic isn't going to derail Franco's new Spain. We are left with the unsettling knowledge that, in the universe crafted by Guillermo del Toro as well as in our own, we are always surrounded by monsters.

Pan's Labyrinth

opens Friday at Cinema 21.