Orca, Siege Demon

Two triggers on the same body point in opposite directions, and the tension between them is the whole design. The first grows the demon on every creature death, yours or the opponent's, turning any board-wide attrition into free counters and rewarding the sacrifice shells that already treat creatures as ammunition. The second converts that accumulated size into a fatal parting shot: when the demon dies, its power splits as damage among any number of targets, so the counters you spent the game piling on become a modular removal spell or a lethal reach at the exact moment the body is answered. The result is a threat that punishes both natural responses to it. Chump-blocking and sacrificing feed the first ability; removal and combat trades trigger the second. The opponent's cleanest out, killing it, is precisely the line that hands you a scaled burst divided wherever it hurts most. Trample keeps the growth honest on the attack, ensuring the pile of counters translates to real pressure rather than getting walled by a single blocker. It belongs to the tradition of black-red demons that demand a sacrifice-heavy shell to earn their payoff, but the death-damage clause gives it a property rare for a creature this size: it is never fully dead, because dying is when it does its most decided work.