When you duel Marik in the Pyramid Set "Penguin Soldier." When Marik attacks it, the effect will be activated.Select "Yes" when you are asked to return a card to your hand and return the attacking monster to Marik's hand. When you are asked if you want to return another monster to your hand select"No". After the card is returned Marik should set another card on the field on the SAME turn which is against the rules.