Atraxa, Martyr of Mirrodin

Flying, menace
Sacrifice Atraxa, Martyr of Mirrodin: Proliferate, then proliferate again.
During each end step, if a creature the turn player controlled died this turn, you may pay 3 life. If you do, return Atraxa, Martyr of Mirrodin from your graveyard to the battlefield tapped.
"I am divinity perfected."