Sprawling Mass

Trample
When Sprawling Mass enters the battlefield
create X 1/1 colorless ooze creature tokens.
At the beginning of each upkeep sacrifice
a black ooze creature and put a +1/+1 counter
on Sprawling Mass. At the beginning of each
end step, if you control no colorless ooze
creature tokens, return Sprawling Mass to
your hand.