A phrase supplanting supercalifragilisticexpialidocious, used when one does not know what to say in reference to another person or situation, especially when one does not give a shit: As in,
Guy: "You know, if Link acquires 100 skulltulas, he will get a special reward, but it takes almost the whole game to get all of them, so what is the point, the game is over by the time you get the reward blah blah blah..."
You all miss the point. mkay, as in the South Park satire, was used by a smug, patronising teacher who says it after a lesson in a tone of fake understanding and empathy with his listeners. Nobody would use it as a substitute for 'okay' except tongue-in-cheek, mkay?