Power Stone Promo

At the beginning of your turn, add {B}. Once each turn, you may put a +1/+1 counter on target creature. {Lns}Creatures that have received a counter this way are indestructible during combat for as long as Power Stone remains on the battlefield. {2}{B}: Destroy target tapped nonland permanent. {T}, remove Power Stone: Until end of turn, creatures you control double their power and gain trample.