What's a flea flicker? A flea flicker is a trick play that takes advantage of football's forwards and backwards passing rules. In it, the quarterback will hand the ball to a running back, who will run forward just like he usually does. The defenders will follow the ball and try to tackle him. Before the defenders close in, the running back will stop and throw the ball backwards to the now open quarterback. From there, the quarterback can make a forwards pass an open wide receiver or tight end as long as he is behind the line of scrimmage.
Check out this example: