Ninjitsu Art Notebook of Mystery
If your opponent controls a card: You can Set up to 1 "Ninja" monster, and up to 1 "Ninjitsu Art" Spell/Trap, except "Ninjitsu Art Notebook of Mystery". These cards come from your Deck and/or GY, but only 1 can come from each. If this Set card on the field is sent to the GY: You can target 1 face-up monster on the field; change it to face-down Defense Position. You can only use each effect of "Ninjitsu Art Notebook of Mystery" once per turn.