Save the Green Planet(2005)

Lee Byeong-Gu is a sensitive, blue collar sad sack hopped up on conspiracy theories and sci-fi films whose life has been derailed by one bad break after another. Yet he knows there's no such thing as bad luck. The only thing that could have made such a mess of his life are aliens. Specifically, Andromedans. Nasty, disgusting Andromedan aliens who have infiltrated human society. Sly Andromedans who are planning to destroy our planet at the next lunar eclipse. The one alien possessing the Royal Genetic Code needed to contact Andromeda's Crown Prince and stop the destruction just happens to be his old boss, CEO of Yuje Chemicals, Kang Man-Shik. So, with the help of his circus-performer girlfriend, he sets out to kidnap Kang and torture him until he confesses to his alien identity and stop the invasion. Of course, it's hard to confess to something that's just a delusion in a sick man's mind.