Ravenous Vampire

Flying (This creature can't be blocked except by creatures with flying or reach.)

First strike (This creature deals combat damage before creatures without first strike.)

At the beginning of your upkeep, you may sacrifice an artifact. If you don't, tap this creature and it deals 2 damage to you.

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.

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

At the beginning of your upkeep, sacrifice a creature if you don't control an Ogre.

Menace, trample

At the beginning of your upkeep, you may sacrifice an artifact, enchantment, or token. If you don't, tap this creature.

Flying

Whenever this creature attacks, you may sacrifice another creature. If you do, put a +1/+1 counter on this creature.

Whenever another nontoken creature dies, draw a card.

At the beginning of your upkeep, any opponent may sacrifice a creature of their choice. If no one does, transform this creature.