Twilight Ninja Kagen

You cannot Pendulum Summon monsters, except "Ninja" monsters. This effect cannot be negated. Once per turn, when your "Ninja" monster declares an attack: You can make that monster gain 1000 ATK until the end of the Damage Step (even if this card leaves the field).

You can Tribute this card, then target 1 "Ninja" monster you control; it gains 800 ATK until the end of this turn.