Hellion Eruption
A one-sided mass conversion: sacrifice all creatures you control, then rebuild it as uniform 4/4 Hellions. The math is the whole tension. Trade a single token and you launder it into a 4/4; feed in a swarm of one-drops and you upsize your entire battlefield to a wall of fat bodies in one turn. Red rarely gets to manufacture this kind of muscle, and almost never gets to convert its own go-wide tokens into something that breaks ground stalls; the usual red answer to a clogged board is to burn through it, not to grow past it. The sacrifice clause does double duty, clearing chaff and triggering whatever death payoffs you have stacked behind it, so the cost is more than the new bodies it buys. The discipline is that the conversion scales only to your own commitment: pour in too little and you have spent six mana to make one creature marginally bigger, and the fresh Hellions arrive summoning-sick, so you cash in your developed attackers for power that cannot swing the turn it lands. It rewards a board that is already wide and already exhausted of its attack step, which is a narrow window, but inside it the upgrade is dramatic in a way few red cards can match.
