Sita Varma, Masked Racer

Exhaust exists to solve a pricing problem with expensive activated abilities: an engine you can tap once for a big payoff is hard to cost, because a repeatable version of the same effect spirals out of control. Here the swing is paid for by that single-use cap, and the payoff is a board-wide flattening that rewards going wide. The activation stacks X counters onto the body first, then optionally rewrites the base power and toughness of every other creature you control to match Sita Varma's power. Because her stat line is asymmetric (2/3), the other creatures do not become copies of her; they inherit a square line equal to her power alone, and a crowd of small green-blue bodies all snap to the same number at once. Since exhaust carries no timing restriction of its own, that transformation happens at instant speed: the counters and the anthem land in response to a block or a removal spell, and because the effect reads base power and toughness after the counters resolve, the size of the swing scales with how much mana you sink into X. A repeatable version would be oppressive; the one-shot version stays a genuine decision about when the board is wide enough and the mana free enough to spend. What she asks for is a specific board state rather than a generically strong body, and she commits to the exhaust constraint fully instead of hedging it with a smaller repeatable mode.