Gor, the Crusher

Cast this spell only if you have 3 or more instant or sorcery spells in your graveyard.
Whenever a land leaves the battlefield, reveal the top card of your library. Deal damage equal to its converted mana cost to each opponent. If its converted mana cost is greater than the amount of commanders you control, you gain life equal to the amount of damage dealt this way.
{t}{r}: Destroy target land.