Exotic Curse

Domain ties an effect's strength to the number of basic land types you control, paying a deck for the color diversity its manabase was already chasing. Stapled to a removal aura, that scaling produces a debuff that ranges from a single point to a full -5/-5 depending on how greedy your lands are. The aura form is the clever part, not a drawback. A sorcery-speed -X/-X would size up once and fade; binding the penalty to an Aura makes it permanent, so a creature you can only shrink to 2/2 today still dies on its own the moment you assemble your fourth and fifth land types. The effect grows alongside your board across turns instead of resolving and vanishing. The price is board commitment most decks would refuse: at one or two land types it barely scratches anything, and you are betting you will reach the full spread before the game decides itself. The ceiling is where it earns its keep. With all five basic land types online, this kills most creatures outright and stands as a permanent toughness tax on the rest. It is domain in its purest reward-the-greedy form: nearly inert in a focused two-color shell, lethal in the rainbow piles where every basic land type the mechanic counts is already part of the plan.