Trap Game - n - the occurrence when a favorite instead falls flat on their face for any one of a variety of reasons, including, but not limited to: having their eyes on the game following instead of the one immediately ahead, overlooking an unheralded underdog, and coming off a difficult, emotional victory the week prior.
Now, I'm an English teacher, so no vocabulary word goes without an accompanying example: In 2014, the then 4-1, Pac-12 North leading Cal Bears were followed a dramatic road win with a Trap Game against the Washington Huskies. They were caught off-guard and subsequently humbled in a 31-7 defeat.