Magmaw

There is no tap symbol, no once-per-turn line, no cap of any kind: the only throttle on this engine is one generic mana and a nonland permanent to feed it. That absence is the whole design. As long as expendable fodder remains and mana is open, the activation fires again, which makes this a converter rather than a finisher. It turns tokens, creatures with death triggers, or permanents that have already done their job into instant-speed pings, each small enough to look harmless and frequent enough to matter: a mana dork picked off, an attacker finished in combat, a planeswalker chipped down. The real value hides in the order of the cost. Because the sacrifice sits before the colon (part of the activation cost, not a triggered effect), an opponent never gets a window to remove the doomed creature in response. You can sandbag a body against targeted removal and still wring a damage out of it on the way out. What the design asks for in return is a board that manufactures disposable nonland permanents faster than the table can punish you for owning a flimsy 4/4 for five. The damage is trivial; the volume is the point. Feed it enough and the trickle becomes a hose.