Play your whole library

Crovax enters with four +1/+1 counters on it. At the beginning of your upkeep, you may sacrifice a creature. If you do, put a +1/+1 counter on Crovax. If you don't, remove a +1/+1 counter from Crovax. : Crovax gains flying until end of turn.

Rather than pay the mana cost for a spell, its controller may discard a card that shares a color with that spell.

: The next time you would draw a card this turn, you gain 5 life instead.