Hamletback Goliath

Most snowball creatures grow on a clock you control: a counter per attack, a counter per upkeep, a curve you can plan around. This Giant flips the trigger outward and makes it indiscriminate. It feeds on every other creature that enters, yours and your opponents' alike, and it pays out in that creature's power rather than a flat number. A board stall where everyone keeps deploying fatties is not a problem for it; it is fuel. The 6/6 inflates by exactly what those bodies were worth on the way in, which means the player who threatens to win on the back of a wide, beefy board is also feeding the one creature that punishes them for it. The constraint that keeps it honest is its own cost and the dead turn it lands on: at seven mana it arrives well after the board is supposed to be developing, and it does nothing the moment it hits. The payoff comes only if creatures keep entering afterward, which is why the natural homes are token engines and sacrifice-and-recur shells that were already happy to keep replaying bodies. The indiscriminate wording cuts both ways: it makes the Giant a magnet for go-wide decks, but it also turns every opposing creature into accidental growth, so the slowest grind is exactly where it gets out of hand. A finisher whose ceiling is set entirely by how busy the board gets, regardless of who made it busy.