Endless One
The blank check given a body. There is no fixed rate to evaluate, no body to compare against the cost, because the body is the cost: every mana you pour in becomes a +1/+1 counter, so a creature with no power and no toughness printed scales linearly with whatever you can pay. That structural openness is the whole point. It slots into any color, any curve, any deck, because it never overshoots; on turn two it is a 2/2, on turn nine it is a nine-counter threat, and it is always exactly as big as the mana available. The counter framing matters more than a flat stat boost would: it makes the creature a legitimate target for anything that doubles, moves, or feeds on +1/+1 counters, turning a colorless filler curve-topper into a piece that proliferate decks and counter-matters builds can exploit. The cost to all this flexibility is fragility of a specific kind: with X at zero it dies as a state-based action before it does anything, and unlike a card with printed stats it carries no floor, no guaranteed body if you are tapped out. What you get is a creature that is honest about being mana, nothing more and nothing less, which is exactly why it has quietly found homes across every era of colorless ramp since Eldrazi designs first needed a sink for excess mana.
