Unnatural Grove

Unnatural Grove enters the battlefield tapped.
{t}: Add {g} to your mana pool.
{t}, pay 1 life: Add {b} to your mana pool.
Whenever you cast a green instant or sorcery spell, you may sacrifice a creature with converted mana cost equal to or greater than that spell's converted mana cost. If you do, copy that spell.
When Unnatural Grove is put into a graveyard from play, exile your graveyard.