Granitic Wurm

Whenever Granitic Wurm deals damage to a creature, put a -1/-1 counter on it. Granitic Wurm gets +1/+1 for each creature under all opponents' control with a -1/-1 counter on it. Whenever a -1/-1 counter is put on a creature, you may pay x, where x is the amount of -1/-1 counters on it. If you do, put another -1/-1 counter on it.
An unstoppable force that drains the energy from all around it; it makes rock look even more lifeless.