The Eater of Worlds

The Eater of Worlds enters the battlefield with
{x} +{1}/+{1} counters, where {x} is equal to
the amount of Black Mana used to cast this card
When The Eater of Worlds takes damage remove
that many +{1}/+{1} counters instead and create a
0/0 Black Wurm Horror creature token with that
many +{1}/+{1} counters on it.