Frostwalla

Green rarely gets a mana sink this clean, and this one asks for exactly one thing: a single mana from a snow source. That price is the whole design. The activation is capped at once per turn, so the sink cannot spiral: no matter how much snow mana sits open, the body tops out at a 4/4 for the turn, one activation deep, at no card cost. That once-per-turn clamp is the trade that buys the cheap price tag. A pump you could repeat freely with mana would have to cost more than a single snow pip; locking it to one use per turn is what lets the ability come at rock-bottom rate. The catch lives in the word "snow." The engine runs only if the mana feeding it carries the snow supertype, which means the deck around it has already paid the color-and-supertype tax to run snow lands and rocks. That is a real deckbuilding commitment, not a free upgrade you slot into any green shell. This is a creature whose value is a repeatable, efficient body-boost rather than a splashy trigger, and its niche is defined by the snow premise it demands more than by the ability itself. Outside a snow shell it is a vanilla 2/2 with a dead line of text; inside one it is a resilient threat that flips a favorable block or turns a race without ever asking for a card in hand.