Magician's Rod

When this card is Normal Summoned: You can add 1 Spell/Trap from your Deck to your hand, that mentions "Dark Magician". During your opponent's turn, if you activate a Spell/Trap Card or effect while this card is in your GY (except during the Damage Step): You can Tribute 1 Spellcaster monster; add this card to your hand. You can only use each effect of "Magician's Rod" once per turn.