Sanguine Swamp

Put a storage counter on this land if at least 1 creature has entered the graveyard from the battlefield.
{t}: Add {b}
{t}: 3{b}{b}: Destroy target creature, Activate this ability only if there are 5 or more creatures in all graveyards.
{t}, Remove 2 storage counters: Each opponent loses 1 life and you gain life equal to the amount of life lost this way.