Gyrus, Master of the Dead

Gyrus, Master of the Dead enters the battlefield
with a number of +1/+1 counters on it equal to
the amount of mana spent to cast it.
At the beginning of your upkeep and whenever
Gyrus, Master of the Dead attacks choose a
creature in a graveyard with power less than
Gyrus, Master of the dead and create a token
copy of that creature except it is a black Zombie
in addition to its other types.