He’s forced to travel back to 1969 to prevent an evil alien (a shockingly effective, nearly unrecognizable Jemaine Clement of Flight Of The Conchords, playing sort of a psychotic extraterrestrial-biker serial killer) from destroying the world by killing Brolin. Smith is aided in his quest by an elfin, time-jumping alien with psychic powers played by another Coen brothers veteran, A Serious Man star Michael Stuhlbarg.