at SFlix. The video Mercy (2005) presents an alt-country ode consisting of a single lyric — "Oh why do I keep on hurting you" — which Kjartansson, standing alone with a guitar, sings over and over in front of the camera like an actor perfecting his role. Now plaintive, now crass, now searching, now pleading, the line takes on a haunting quality not quite undercut by the tune’s tongue-in-cheek twang. The work introduced a recurring motif in the artist’s repertoire: the slick-haired singer, a persona Kjartansson has honed in real life as front man for the synth-heavy Reykjavík rock band Trabant, now on hiatus. The band’s performances — as seen on YouTube, anyway — have been blowout affairs, full of rock ’n’ roll swagger and screaming teenage fans. Mercy was a first step toward connecting this sassy streak with the artist’s maturing explorations of Icelandic identity.