What It Does
The iron, taken apart — the corrosion is the whole argument, and the corrosion does not cut, and the corrosion wins by the slow argument that the edge was always the one who was losing. The blade goes where the rust says, and the rust says back to the ore.
The Cost
Circle 2 · Poison · Exchange: breath — casting time one round. On the ladder in The Veil, the breath rung is the price.
The Failure
The corrode holds the iron a beat too long, and the decay keeps the tension — the iron is the one who rusts, and the one who rusts is the blade that was already the parry.
In Stories
The journeyman's poison spell; the one the camp casts when the edge is the argument and the arithmetic is the one who has to win.
The door's scale anchor is Scorpion — the dragon casts it without thinking, which is how a reader learns the shape of the thing.