The Chicago Tigers of the American Professional Football Association (APFA) played their first and only season in 1920, the first year of the league (1920), and have the distinction of being the first NFL team to fold.
According to Emil Klosiinkski in the book, Pro Football in the Days of Rockne, the Tigers' main offensive weapon was their passing game.
This specifically referred to the passes thrown by Johnny Barrett and Milt Ghee to Jack Meagher and Oscar Knop.
The Tigers finished the season with a 2–5–1 record and, as allegedly promised, dropped out of the league.
However, there are three problems with this story: first, the Tigers played two more league games after losing to the Cardinals; second, O'Brien was willing to let the Decatur Staleys play in Chicago the following season (in fact, it was the Staleys that proved to be the Tigers' actual last league opponent); and third, there is no contemporary evidence for the challenge.