Martyr of Bones

Graveyard hate priced in color devotion: the exile ability costs one mana, but the variable that actually scales it is how many black cards you can flash from your grip. Reveal X, sacrifice the body, and you exile up to X cards from a single graveyard, so a hand committed to mono-black already sets a wide ceiling. That ties the answer to a deckbuilding choice rather than a board state. The more devoted the deck, the larger the exile, and a one-drop that eats itself for the activation keeps the whole package nearly free. This is a creature built to be cashed in rather than swung: the body is a delivery mechanism, and the moment it does its job it is gone. The constraint cuts both ways. Against a deck that fills its yard a card or two at a time, you can strip a chunk and shut off recursion in a single instant-speed window; against a deck that buries six cards in one turn, your hand caps the answer regardless of how black it is. The reveal hides nothing, since the opponent watches exactly how committed your grip is before the exile resolves. As a self-sacrificing eraser aimed at one graveyard, it asks the deck to honor its color discipline up front, then pays out in proportion to that discipline.