A play on words (to the Read and React technique).
Two or three defenders take their respective stances at the line of scrimmage. A Center snaps a ball to a lone back who takes off at full sprint to either sideline. A coach calls out the snap count trying to draw the defenders offside. On the snap the defenders fire off the line and pursue the ball carrier.
When time and or manpower allow, two offensive linemen and an extra ball carrier can be used to perfect the defenders ability to "find" the football.