Nim Replica

Cast off any color and you still pay black to fire it: that is the bargain at the heart of this artifact creature, and it is exactly what the cycle of Replicas was built to do. Each one is a colorless body whose activated ability demands its proper color of mana, so a deck running no Swamps can still play this on the board, then find itself unable to wring the -1/-1 out of it. The body is fragile by design (a 3/1 dies to almost anything), but the ability turns the creature into a deferred removal spell: hold it, block with it, and when the math is right, sacrifice it to shrink a problem or finish off something already wounded. It is removal stapled to a creature you were going to play anyway, with the activation cost set high enough that the trade is rarely free. What carries this design is the lineage, not the rate. The Replica cycle was an early, deliberate experiment in colorless cards that still cared about color through their costs, a tension an artifact-heavy era returned to again and again as it tested how far a set could push toward universality before the colors reasserted themselves. This one carries black's small-creature attrition into any shell, which is the whole pitch and the whole limit of what it does.