Blast Zone

Blast Zone enters the battlefield with a charge counter on it.
{t}, Add {c}.
{x}{x}, T: Put X charge counters on Blast Zone.
{3}, {t}, Sacrifice Blast Zone: Destroy each nonland permanent with mana value equal to the number of charge counters on Blast Zone.

Helgen had been razed by dragon fire, and then the Goblins followed the smoke clouds to an empty town.