Krosan Druid

Two cards folded into one card slot, with the choice deferred until you cast rather than made when you build. For three mana you get a 2/3 body, an unremarkable green blocker that holds the ground and asks nothing of your draw. Pay the additional and the same creature also gains you ten life, a burst that on its own would justify a small enchantment or a dedicated spell. The kicker structure gives green a floor that never rots in hand and a ceiling reached only once the game has run long enough to want it. The lifegain is gated behind the kicker condition rather than the cast: the trigger checks specifically that the extra cost was paid, which keeps the cheap mode honestly cheap and preserves the promise kicker was designed around. You never commit to the expensive version at deckbuilding time, only in the moment your mana overflows. That is the mechanic's whole appeal in miniature, a creature you would run anyway that converts flooded late-game mana into a meaningful life swing without ever forcing a decision up front. It is a deliberately modest illustration of the idea, sized at common power level, but the design logic is the same one that makes kicker one of green's most regret-free tools: a body that trades early and banks a ten-life payoff for later.