Anivia, the Cryophoenix

Flying, Hexproof
Whenever Anivia, the Cryophoenix would die,
instead exile it and create a 0/2 blue Legendary
Egg creature token named Eggnivia with
defender and "At the beginning of your upkeep,
sacrifice this creature. When you do, if Anivia, the
Cryophoenix is in exile, return it to the battlefield
under your control."
Whenever another snow permanent enters the
battlefield under your control, tap target creature
and draw a card.