This strategy for stopping the clock became legal in the early 1990s and has become standard operating procedure around the league since. It is a legal form of intentional grounding, since the quarterback is not looking to avoid a sack and immediately throws the ball to the ground after taking the snap. It is treated as an incomplete pass. For it to be legal, the quarterback has to be under center. Previously, quarterbacks had to throw the ball out of bounds to stop the clock. Without a doubt, it's one of the more comical-looking plays in football, but one that is often crucial to sustaining last-minute scoring drives.