Convergent Darkness

At the beginning of you upkeep you may sacrifice
a black creature you control then put a Dark
Counter on this card
{b}{b}{b}: Sacrifice a black creature you control,
put a Dark Counter on this card
{b}{b}{b}{b}: Sacrifice this card, create a black
Living Darkness creature token with X/X where
X is equal to the number of Dark Counters on
the enchantment