The Chilean feature Crystal Fairy & the Magical Cactus, which opens Friday at Music Box, feels anecdotal, even tossed-off. Set over a few leisurely days, it centers on Jamie (Michael Cera), a spoiled, insensitive American living in Santiago and obsessed with drugs. Along with his Chilean roommate, Pilo (Augustin Silva), and Pilo’s two brothers, he plans to take a road trip to a remote town called San Pedro, score a hunk of its native cactus, known for its hallucinogenic properties, and have an epic trip on the beach.

Silva wrote a rough script for Crystal Fairy in a few weeks, basing the story on an experience from his early 20s. (In interviews he claims that nearly everything in the movie really happened to him.) Cera would be his autobiographical stand-in, and Silva’s three younger brothers would play the travel companions. Hoffmann, another friend, would fly down from the States to play the annoying American who tagged along on Silva’s drug trip. The movie took about as long to shoot as it did to plot out, with most of the dialogue improvised on the spot or written just before the cameras rolled.

Directed by Sebastian Silva