Stag Beetle

Its size is a referendum on the board state. Cast it into an empty battlefield and it enters as a 0/0 with no counters, dying to state-based actions the instant it arrives; cast it into a crowded one and it can dwarf everything around it. That it counts other creatures, including your opponents', makes it a curious piece of tempo logic: it grows fattest exactly when the game has stalled into a clogged ground, the moment a giant green blocker matters most, and it stays small in the early turns when you would most want a body. The counter math is permanent once it resolves, so unlike effects that rescale with the board, this is a one-time snapshot taken on entry; if other creatures leave the turn after, the Beetle keeps its bulk while its size no longer reflects the board. Fixing the power on arrival is what sets it apart from the dynamic-power lords that came later, and it is also the wrinkle that makes it a genuine engine card rather than just a fatty: the counters are real +1/+1 counters, fair game for any proliferate, doubling, or counter-payoff shell that wants a large pile dropped onto a single permanent in one shot. A 0/0 with a printed cost is a strange object on its own, but as a delivery mechanism for a stack of counters scaled to a full board, it has aged into something its early-era design never anticipated.