What usually happens when a Division 2 team plays against a bigtime D-1 powerhouse? The D-2 team gets run over. As a matter of fact, a top 25 D-1 team has NEVER in history lost to a D-2 team. Typically, big schools schedule smaller ones for their first game of the season for a guaranteed win to get the fan base excited and to prep their guys in a glorified scrimmage.
Except for last Saturday. Michigan had paid $400,000 to Appalachian State to come play patsy in the Big House (nicknamed this because their stadium holds 120,000 fans, more than 30x as many than attend Appalachian State). Michigan was rated the #5 team in the nation, with many returning seniors who had turned down joining the NFL for a very legitimate chance to win the national championship. Nobody gave Appalachian State a chance in hell, but Appalachian State entered the game as the 2 time defending Division 2 national champions and owners of the longest winning streak in college football.
Enter drama. In front of 109,000 screaming Michigan fans, little Appalachian State pulled off the biggest upset in sports history. Yes, this is bigger than the U.S. hockey team beating the Soviet team (same level of players).