Wasitora, Nekoru Queen

The combat damage trigger is the whole engine, and it is built as a Rock-Paper-Scissors that always resolves in your favor. Connect once and the defender must sacrifice a creature they wanted to keep, or, if they have none, hand you a 3/3 flier that adds to your board and keeps the pressure on. Flying and trample on a 5/4 body are not incidental here; they exist to make the trigger easy to land, since chump-blocking a flier is difficult and trample punches damage through whatever survives. The design leans on Edict-style sacrifice (the defender chooses which creature dies, so you never pick off their best threat directly), but attaches it to a repeatable clock rather than a one-shot spell like Diabolic Edict or Chainer's Edict. What makes the loop nasty is that the two outcomes reinforce each other over time: an empty board means tokens, a full board means attrition, and every successful attack narrows the defender's options for the next one. Casting cost splits across three colors, which anchors the card to a Jund identity and asks for a manabase to match, but the payoff is a single creature that threatens to end a stalled game by inches: either grinding boards to zero or building a squadron of flying Cat Dragons that do the grinding for it.