Can only be equipped to a "Penguin" monster. The equipped monster gains 800 ATK. When the equipped monster inflicts battle damage to your opponent: You can return 1 card your opponent controls to their hand. If a face-up card(s) your opponent controls leaves the field by the effect of a "Penguin" card, and it is returned to the hand or banished: Negate the effects of that card(s), as well as the activated effects and effects on the field of monsters with the same original name until the end of the next turn. You can only use this effect of "Penguin Sword" once per turn.