Tainted Adversary

Deathtouch
When Tainted Adversary enters the battlefield,
you may pay {2}{b} any number of times. When
you pay this cost one or more times, put that
many +1/+1 counters on Tainted Adversary,
then create twice that many 2/2 black Zombie
creature tokens with decayed. (A creature with
decayed can't block. When it attacks, sacrifice it at
end of combat.)