Furnace Gremlin

The pump ability and the death trigger are the same lever pulled twice. Every activation of the firebreathing costs mana now but banks value later: the incubate is sized to the creature's power, so the more you've pumped it in a given turn, the fatter the Incubator token it leaves behind when it dies. That converts a small aggressive body into a resource that resents being killed, which is an unusual posture for a two-drop. Trade it in combat and you've paid for the trade with an Incubator token waiting to transform; block with it and the same math applies. The design leans on the tension between spending mana to swing harder and spending it to make the eventual replacement bigger, and both choices route through the identical activation. Because incubate defers the payoff behind a separate flip cost, the value isn't free: the token sits inert until you commit again, which keeps a would-be snowball honest and gives an opponent a window to answer the Incubator before it becomes a body. What makes the gremlin worth building around is that its worst-case outcome (dying) is the trigger it's designed to reward, so the pump ability doubles as a way to set the price of your own removal for the other player.