Tainted Fortress

Whenever you gain or lose life, put a +1/+1 counter on Tainted Fortress. Pay 3 life: Choose 1- -Tainted Fortress gains lifelink until end of turn. -Until end of turn, Tainted Fortress can block any number of creatures. Pay 15 life: All creatures lose all abilities and have base power and toughness 1/1. Activate this ability only if Tainted Fortress has 15 or more +1/+1 counters on it.