Jioh the Gravity Ninja

If this card is Normal/Special Summoned, or flipped face-up: You can target up to 2 face-up monsters on the field; change them to face-down Defense Position, and if you do, any opponent's monsters that were flipped by this effect cannot change their battle positions. If a monster on the field is flipped face-up, while this monster is face-up on the field (except during the Damage Step): You can target 1 card your opponent controls; destroy it. You can only use each effect of "Jioh the Gravity Ninja" once per turn.