It's just a phrase that you might try to use if you think the Earth is about to be destroyed and you see a robot like Biff nearby who might be able to do something about it. Whether two Tennessee teams playing horrible ball is really like the end of the world is unclear because I've seen UTenn and Vandy playing like that sometimes. But maybe if you say Klaatu barada nikto at a Tennessee game the play will get better, or they may just mistake you for a crazy Slovakian brother since nikto apparently means anybody over there east of the the Czechs.