Chittering Skitterling

The gate here is the whole design: a repeatable card-draw engine that stays completely inert until an opponent has three or more poison counters. That toughness of 4 on a one-power body tells you what the creature is for before the ability ever unlocks. It is meant to sit and block, weathering early aggression while the poison plan does its work elsewhere, and only then flip on as a sacrifice-fueled draw outlet. The corrupted threshold does two things at once: it prices the ability out of any deck not committed to poison, and it turns the card into a payoff rather than an enabler. You cannot use it to start the poison clock, only to profit once someone else has advanced it. The once-each-turn clamp keeps it from becoming an explosive combo piece, so what you get is grind, not burst: one card per turn, each bought by feeding an artifact or creature into the maw. That fodder requirement rewards the wide, expendable board states poison decks tend to build anyway, which is the quiet elegance of the thing. It asks nothing you were not already doing and pays you for having a threshold-based archetype in the first place. A conditional engine, gated behind a wincon that most tables never reach, built to reward the one shell that always does.