Despite the contemporary setting, this offbeat British comedy was inspired by the career of 80s avant-pop musician Chris Sievey, who performed wearing a giant papier-mache head and calling himself Frank Sidebottom. Director Lenny Abramson and screenwriters Jon Ronson and Peter Straughan couldn’t be more determined in their courtship of cult status: their title character (Michael Fassbender), hiding beneath his ovoid mask 24/7, calls to mind every loony-bird rocker from Roky Erickson to Daniel Johnston, and the players in his backup band (among them Maggie Gyllenhaal) are comically icy krautrock archetypes. Playing Nick Carraway to this geek Gatsby is a talentless songwriter (Domnhall Gleeson) who joins the band on keys, posts video from its secret recording sessions to YouTube, and lands it a star-making gig at South by Southwest. The movie’s hipness quotient far outweighs its laugh quotient, though there’s really no limit to the amusement of seeing someone bump around blindly in an oversize head.