Double Iris Magician

[ Pendulum Effect ] 
Once per turn: You can target 1 DARK Spellcaster-Type monster you control; apply this effect to it, then destroy this card. Once applied, double any battle damage that monster inflicts to your opponent this turn if it battles an opponent's monster.

[ Monster Effect ] 
(This card is always treated as a "Pendulum Dragon" card.)
If this card is destroyed by battle or card effect: You can add 1 "Pendulumgraph" card from your Deck to your hand.