With the exception of the tot-friendly, adult-numbing “The Good Dinosaur” (2015), “Luca” is as much of a trifle as the Pixar Animation Studios have ever come up with. That sounds like a harsh judgment, but in light of Pixar’s recent track record there are worse things you could say. My own feeling, while far from universal, is that in the last five years some of the most ambitious Pixar projects have gone off the track (like the Day of the Dead Mexican fantasia “Coco,” which was gorgeous but dragged on, or “Incredibles 2,” which despite knee-jerk raves was notably less incredible than the first one). “Luca,” set in Italy in the ’50s, is modest to a fault, and at times it feels generic enough to be an animated feature from almost any studio. But it’s a visually beguiling small-town nostalgia trip, as well as a perfectly pleasant fish-out-of-water fable — literally, since it’s about a boy sea monster who longs to go ashore.
The early parts are set under the sea, and if you’re thinking “The Little Mermaid” meets “Finding Nemo,” you wouldn’t be too far off. “Luca” is a film for kiddies that unabashedly recycles old formulas. Yet it’s built around one original minor trope of fairy-tale nonsense: In this movie, when a sea monster like Luca (Jacob Tremblay), with his electric-blue fauna hair and aqua skin and Creature from the Black Lagoon gill ears, leaves the water, he instantly converts to human form; when he goes back into the water, he reverts. If this back-and-forth metamorphosis feels overly convenient (and not quite explained), the movie still has fun with it, especially when the conceit turns into a constant threat of blowing the sea monsters’ cover.
Luca is desperate to go ashore, despite the dire warnings of his parents, the brassy Daniela (Maya Rudolph) and lumpish Lorenzo (Jim Gaffigan). Crawling up on a rocky beach, he becomes a curly-haired, big-eyed kid who looks Italian but still sounds, in the performance of Jacob Tremblay (from “Wonder”), like a wide-eyed American everykid. He meets the teenage Alberto (Jack Dylan Grazer), who’s like the sea-monster version of a Jonas brother, and who’s been on land for a while, living in an abandoned stone castle column as a real boy. Alberto is alone except for all the junk he collects, but with his reckless high spirits he’s got a dream: He’ll do anything to own a Vespa! That’s right, the fabled Italian motor scooter that was introduced in 1946.
“Luca” is a bit colorless until the two boys arrive in the sloping fishing village of Portorosso, with its crooked pastel buildings and winding streets, its sun-dappled town square dotted with a trattoria and a pescheria, its poster of “La Strada.” So quaint! So picturesque! So Fellini meets De Sica meets your trusty postwar travel agent! Once there, they discover there’s going to be a local competition, the annual Portorosso Cup triathlon (swimming, pasta eating, bike riding), the winner of which will receive a prize of enough money to buy a Vespa. Luca and Alberto team up with the feisty, flame-haired Giuilia (Emma Berman), who can get them into the race, and they spend some time at her house, quaking under the mostly wordless gaze of her hulking, brooding, one-armed knife-happy fisherman father, Massimo (Marco Barricelli), who lives in mortal fear of sea monsters and makes the tastiest looking pesto pasta, which our two heroes literally stuff their faces with, since they have no idea how to use a fork.
Every so often, an overhead leak or a thrown glass of water will land on their skin and reveal their psychedelically hued sea-monster selves. But only for a few seconds; they snap right back. And that pasta scene aside, they don’t seem to have much trouble adjusting to acting like humans. “Luca” is the first feature directed by Enrico Casarosa, who made the celebrated 2011 Pixar short “La Luna,” and while his images have a perky bravura (especially in a fantasy sequence spun out of the glories of the Vespa), the script, by Jesse Andrews and Mike Jones, is pretty thin stuff.
The two boys help Massimo with his fishing, because they know just where the fish are. Luca learns that what he thought were “fish” in the night sky are actually stars. And Luca’s parents, distressed at his disappearance, show up in Portorosso in their own human guise, dropping water balloons on kids to see if one of them will turn back into their son. The rascally Vespa owner Urkule stands around the town square taunting and kvetching. Someone at the studio needed to send a memo saying that this isn’t quite a plot — it’s a bunch of incidents killing time.
At last, the film arrives at the Portorosso Cup and has some fun with it, as Luca attempts to do the swimming portion of the triathlon in an ancient diver’s suit, only to learn, by the time they’re on bikes, that it has begun to rain, which will turn these sea monsters right back to their natural selves. Will the town accept them? “Luca” resolves that question in as winsomely simple a fashion as it does everything else. It’s a friendly bauble of a film, but it can’t help but make you wonder if Pixar is losing its golden touch.