Phyrexian Obscenity

Flying, Deathtouch, Indestructible, First Strike, Lifelink
Creatures you control with phyrexian mana in their mana costs get +7/+7.
At the beginning of each opponent's upkeep, they must sacrifice a creature or lose 7 life.
Pay X Life and sacrifice Phyrexian Obscenity: Draw twice X cards.