Shimatsu the Bloodcloaked

The 0/0 base is the whole gimmick: this is a creature that dies on entry unless you feed it, and the food can be anything you control. Lands, tokens, spent artifacts, other creatures already on their way out: every permanent on your board is a potential +1/+1 counter, which turns the cast into a one-shot accounting problem rather than a fixed body. The conversion happens as it enters, before the counters can be answered, so what you get is a creature whose size is set entirely by what you were willing to part with at that exact moment. That makes it a sink rather than an engine. There is no recurring value here, no death payoff baked in, no way to recoup the permanents you crack to size it up; you pay the whole cost in board presence at once and hope the resulting body matters more than everything you sacrificed to build it. The trade is brutally direct, and the flavor reads as cleanly as the math: a demon that demands tribute before it will stand up, and the mechanic delivers it literally. Feed it enough and it becomes enormous; feed it nothing and it falls over the instant it arrives. The builds that justify the cost are the ones that have already extracted value from the permanents being fed: tokens that triggered on their way in, creatures with sacrifice payoffs, lands that have done their work. Absent that, it is a pile of cards rearranged into one large attacker.