The star of Marcel the Shell with Shoes on (A24)

If you are not familiar with the words and wisdom of Marcel the Shell from his YouTube videos that have been seen by millions since 2010, no worries. Director Dean Fleischer-Camp’s full-length movie featuring the one-inch half shell, half human creature catches viewers up to speed on his life story.

With one large gaping eye and two feet wearing the titular pink shoes, Marcel is a stop-motion animation/live-action hybrid that could have been dreamed up by a feverish René Magritte. In a string of droll coming-of-age (mis)adventures, Marcel (voiced by Jenny Slate) faces the confounding changes that life throws his way. He lives a quiet life with his no-nonsense, gruff, though loving grandma, Connie (voiced by the ever-dependable Isabella Rossellini), now that his extended family has suddenly and mysteriously vanished. They were tossed out of their home, a sock drawer, when the previous renters split up and left. Marcel’s quest for his kinfolk drives the episodic escapades he undertakes as Dean (played by Fleischer-Camp), a documentary filmmaker, tags along.

Dean has rented Marcel’s domain via Airbnb; it looks furnished straight out of the Pottery Barn catalogue. The filmmaker strikes documentary gold when he discovers that someone else lives in his residence: he films the inventive mollusk speeding through rooms inside a hallowed tennis ball, what Marcel calls a “rover,” or playing taps through a piece of dry cellentani pasta. Taking a page out of Mary Norton’s children’s book classic The Borrowers, Marcel has also turned a found inhaler into a slide, and, for a bed, he sleeps between two slices of white bread.

Perhaps against his better judgment, Dean becomes intimately involved in the squabbles and pleasures of Marcel and Connie. She, like her grandson, has many talents—a green thumb, for one. (Marcel is wary of gardening though; he can’t stand earthworms.) The two especially love 60 Minutes, watch it religiously, and worship reporter Leslie Stahl, whom they consider “fearless”—the veteran journalist has her day in the sun here; her guest appearance might be the next best thing to a Peabody Award.

In the collaboration between the young director and the sensitive, mild-mannered Marcel, the comedy also gently knocks documentary filmmaking, questioning how a filmmaker can remain an objective observer when dealing with a lonely, young subject who seeks a connection. At first, Marcel doesn’t understand their partnership. When Dean explains he has posted online videos of their interactions, the confused Marcel first question is: “On the line?” Connie, though, has little need for Dean. She participates because she hopes the videos will help Marcel come out of his shell, so to speak. She has no qualms telling Dean to go away or shut up.

Given that Marcel’s goal is to “have a good life and to stay alive, and not just survive but have a good life,” many of his observations could serve as universal affirmations. (For example, on basketball, he surmises, “You miss 100 percent of shots you don’t make.”) What might take some acclimation, though, is the baby-like vocal performance by co-writer Slate as Marcel. With a nasally high-pitched tone, Marcel sounds like the world’s most precocious and upbeat five-year-old—his gosh-golly wonderment may take some getting used to. Yet his optimism and the whimsical film are infectious. They will wear down hardened cynics, although some viewers may need to have insulin on the ready.

Still, this is an unusually wholesome movie that effortlessly appeals to adults and kids. It feels as though it was made for both. And at 90 minutes, its running time feels just right. The limelight-loving Marcel knows when to exit the stage.