Is it a brilliant modern dance work, a slo-mo piece of performance art or just another inscrutable music video? The "mystery film experiment" certainly takes the meditative music of Sigur Rós to a new level of complexity. It's also NSFW, thanks to an in the buff Shia LaBeouf, glow-in-the-dark lollipops and body painting that crosses a line not even Gotye dared tread.