Merfolk Skydiver

Proliferate stapled to a repeatable activation is what makes this evasive body more than a small clock in the air: the enters trigger seeds one counter on a creature you control, and the activated ability then compounds every counter already sitting on the board, not just its own. It is agnostic about kind. It grows loyalty on planeswalkers, charge counters on artifacts, poison on an opponent, or the -1/-1 counters holding something else down, provided the counter already exists. That indifference is the whole appeal: it functions as a payoff for any deck already generating counters rather than a card demanding its own dedicated shell. The cost structure keeps it in check: five mana per proliferate activation asks for patience and a board already worth growing, so the card rewards a developed position instead of snowballing early. As a two-mana flier it still has a floor, chipping in evasive damage while the engine assembles. Green-blue has long been the color pair most associated with proliferate and +1/+1 counter accumulation, and this stitches both jobs onto a single creature: it opens the counter pile with its enter trigger and accelerates it later with the ability, giving that archetype a body that does both halves of the work.