Blazethorn Scarecrow

A colorless body that pays nothing in colored mana yet behaves like a Gruul card anyway, because it earns both of its keywords by inspecting the rest of your board rather than your manabase. Control a red creature and it gains haste; control a green creature and it gains wither, so its combat damage maims blockers with permanent counters instead of fading at end of turn. The two clauses reward different commitments. Red company alone leaves you with a hasty three-power swing and nothing else. Green company alone gives you a corrosive attacker that grinds down anything it touches but plods in slowly. Field both and the Scarecrow lands attacking and shrinks whatever stands in its way, trading up against blockers it would otherwise bounce off of. The design sits squarely in an era fascinated with caring about the colors of creatures you already control rather than the colors you can pay for, which lets an artifact slot into a two-color aggro shell as though it had been those colors from the start. The wither half is the sharper of the two: a 3/3 whose strikes leave -1/-1 counters effectively wins fights it has no business winning, since the wall it walks into stays smaller forever while the Scarecrow lives to attack again. It is a payoff that asks nothing of your lands and everything of who you put beside it.