If you have 3 or more "Memento" monsters with different names in your GY, you can Special Summon this card (from your hand). You can only Special Summon "Memento Horn Dragon" once per turn this way. If this card on the field is destroyed by card effect: You can target 3 face-up cards on the field, including a "Memento" card you control; destroy them. You can only use this effect of "Memento Horn Dragon" once per turn.