Number 89: Diablosis the Mind Hacker

2 Level 7 monsters
Once per turn: You can detach 1 material from this card; look at your opponent's Extra Deck and banish 1 monster from it, face-down. At the end of the Battle Phase, if this card destroyed a monster by battle: You can target 1 card in your opponent's GY; banish it, face-down. If a card your opponent owns and possesses is banished face-down while you control this card (except during the Damage Step): You can banish cards from the top of your opponent's Deck, face-down, equal to their face-down banished cards. You can only use this effect of "Number 89: Diablosis the Mind Hacker" once per turn.