Ancient Ooze

Most variable-stat creatures count something cheap and plentiful: lands, creatures by headcount, cards in a graveyard. This one counts mana value, summing the printed costs of your other creatures into a single body, which inverts the usual incentive. The cheap, efficient board that wins most green games does almost nothing for it; what feeds it is expensive fatties, the very creatures you would rather just cast and swing with. That tension is the whole problem with building around it: every big creature you control makes the Ooze enormous, but you already control a big creature, so the Ooze is paying you back in a currency you spent to earn it. Stranded alone it is a seven-mana 0/0 that dies on arrival, since it counts only other creatures and never itself. The reward, when it lands, is a body whose ceiling has no cap, which is the sort of math that reads better on paper than it plays at the table. The card sits in a green tradition of creatures that exist to be the largest thing in the room rather than the most useful, a payoff that asks you to have already won the resource war before it contributes anything. Interesting as a design artifact of an era hungry for scaling stats; harder to justify when a creature of the same investment could simply be a finisher in its own right.