Nightmare Sower

Black rarely gets a shrink effect that fires on someone else's clock, and that timing is what makes this Faerie worth the slot. The trigger cares about spells cast during an opponent's turn, so it pays out precisely when you're holding up mana: every reactive card you were casting anyway (a counterspell, an instant-speed removal spell, a flash threat) now drops a -1/-1 counter onto a creature as a free rider. That inverts the usual math on spellcast-matters payoffs, which tend to reward tapping out on your own turn or building around a permanent you already control. Here the reward comes from playing draw-go and punishing an opponent for untapping into open mana. The counter is the right currency for a slow grind: it permanently lowers toughness, works through indestructible, and stacks across turns to whittle a durable blocker to nothing over a few exchanges. The trigger still needs a legal target, so hexproof and ward blunt it, but "up to one" means an empty board never strands you or wastes the spell that would have triggered it. Lifelink offsets the tempo you spend operating at instant speed, and the evasive body cleans up the last points once the ground has thinned. It belongs to black's control-adjacent value creatures, the ones that want you casting on the opponent's turn rather than developing on your own, rewarding patience with a steady drip of attrition.