“Crystal Fairy” takes a surrealistic trip to the Chilean desert. It’s a clever, natural little film about a young American obsessed with taking mescaline, the Chilean friends who help him achieve his quest and the 21st-century hippie chick who goes along for the ride.

Michael Cera plays Jamie, an irritating, selfish young man who desperately wants to trip on the cooked juice of the San Pedro cactus. Champa, his friend in Chile, acts as Jamie’s mentor and guide. Played by Juan Andrés Silva, Champa is an amazingly patient friend, to the point of sainthood.

Cera’s Jamie, on the other hand, is the movie’s whining, myopic kill-joy. A weasel dressed in pale human flesh, you just want to smack the guy. But Champa and his good-natured younger brothers, Lel (José Miguel Silva) and Pilo (Agustín Silva), carry forth in serenely mellow style, even when they’re not high.

In tune with Jamie’s hallucinogenic quest, “Crystal Fairy” begins with heavy drug use. Jamie and his friends are snorting cocaine at a big, loud party filled with young people. Jamie ends up in conversation with the wildest dancer at the party, Crystal Fairy.

“You’re embarrassing yourself,” he tells Crystal.

Despite his criticism of her hyper-extroverted behavior, Jamie invites this person he’s just met to go to the north of Chile with himself, Champa and his brothers. To ensure that contact between them is maintained, Jamie even gives the probably unhinged person his phone number.

Gaby Hoffmann, the 31-year-old former child actress who appeared in “Uncle Buck,” “Field of Dreams” and “Sleepless in Seattle,” takes on the title role in 34-year-old Chilean writer-director Sebastián Silva’s “Crystal Fairy.” Her wild and crazy character rivals any previous hippie chick character in the history of cinema.

Hoffman’s aggressively free-spirited Crystal terrifies the delicate Jamie. These two are a match made during a bad acid trip.

“Do you think this is gonna be crazy having her with us the whole time?” the controlling Jamie not so much asks as complains.

Jamie quickly suggests the guys dump Crystal at a hostel or a bus stop. The kindly Chileans object. She’s one of them now.

“Jamie,” Crystal says early on, “I feel a lot of aggression coming from you. Is there something you want to talk about?”

Much of “Crystal Fairy” is funny or at least amusing, especially in the many ways that Crystal gets on Jamie’s nerves. In darker ways, the movie can also be unnerving. Some scenes are abrasively frank and painful.

But Silva’s movie is a journey, physically and spiritually. He’s a marvelous filmmaker and storyteller.