Amazoness Archers (MFC-096) [Magician's Force]

This card can only be activated when your opponent attacks and you control a monster on your side of the field that includes "Amazoness" in its card name, or is named "Amazon Archer". All monsters on your opponent's side of the field become face-up Attack Position (Flip Effects are not activated) and as long as they remain face-up on the field decrease their ATK by 500 points. Your opponent must attack with all of these monsters this turn.