In this sly mockumentary, Zak Penn persuades German filmmaker Werner Herzog to direct a documentary on the Loch Ness monster. Herzog explains that he’s less interested in the monster than in the human need to believe, but Penn, acting as his producer, is more consumed by the human need to sell tickets, and behind Herzog’s back he begins shooting faked scenes of the monster and interviews with a bikini-clad model posing as a sonar expert. I can’t imagine how Penn, a Hollywood screenwriter of little consequence, got Herzog on board for this, but it turns out to be surprisingly layered, exploring the legends that surround such Herzog classics as Fitzcarraldo and Aguirre: The Wrath of God and implying that cinephiles are particularly afflicted by the need to believe. Penn directed his own script; he and Herzog were the producers. PG-13, 94 min.