Viroc, the Flightless Reaper

Viroc, the Flightless Reaper is unlockable
Viroc doesn't untap during your untap step
Whenever Viroc, the Flightless Reaper would deal
combat damage to a player, prevent that damage
and create a 1/1 Bird token that is blue, black and
white for each point of damage prevented this way
Sacrifice a bird: destroy target creature
Sacrifice two birds: untap Viroc