A young castaway on a remote island (Paul Dano at his mooniest) discovers the body of another man his age (Daniel Radcliffe at his deadest) washed up onshore, and after he drags it back into the woods and cares for it, the corpse returns to life, becoming his zoned-out man Friday. (Can’t he find a volleyball?) This directionless fantasy, essentially a two-hander for an overtaxed Dano and Radcliffe, marks the feature debut of music video directors Dan Kwan and Daniel Scheinert (DJ Snake and Lil Jon’s chaotic “Turn Down for What”), who cite as their inspirations such music-video-to-legit-cinema crossovers as Spike Jonze (Her, Adaptation) and Michel Gondry (The Science of Sleep, Is the Man Who Is Tall Happy?). This movie is every bit as whimsical as the more established filmmakers’ work but lacks the minimal plotting and strong intellectual component that gives their flights of fancy shape and substance.