Profane Blood Rite

This spell costs {4} less to cast if you have four
or more creatures in your graveyard
Whenever you cast a spell each player loses life
equal to that card's converted mana cost.
{4}{b}{b}{b},{t}:Sacrifice Profane Blood Rite. You
gain 1 life for each creature on the battlefield.
"The price of your knowledge is pain. And we all
will share in it"