Possessed Centaur

Threshold did something quietly subversive: it let a card become a different card mid-game, and this Centaur is the most literal example of the idea. As a plain 3/3 with trample, it is a green body that exists to attack and trade. Reach seven cards in your graveyard and it defects: the body grows by a point in each direction, its color shifts to black, and it picks up a repeatable kill switch aimed squarely at the color that printed it. That last clause is the wrinkle worth dwelling on. A green creature that destroys green creatures is a deliberate flavor inversion (the Horror in the type line is the corruption made mechanical), but it is also a real-game asymmetry: in a green-on-green board, one side's attacker suddenly answers the other side's threats for a tap and . The constraint that pays for all this is the graveyard count, which means the card rewards a deck already built to fill its own yard rather than asking you to fight for the upgrade. Until the condition flips you are holding a trampling beater and a promise; after it flips you are holding an attacker that also moonlights as targeted removal. The design captures threshold's central tension cleanly: the cost is not mana but the slow accumulation of a dead resource, and the payoff is a card that quietly stops being the thing your opponent prepared for.