Karumonix, the Rat King

Toxic was designed to make poison approachable to decks that could never assemble a full-speed infect clock, and this Rat King is the payoff piece the mechanic quietly needed: a tribal lord that hands out its poison keyword to a swarm rather than betting everything on one evasive threat. The card's real trick is that toxic stacks additively across a board, so a wide table of Rats each dealing a single poison counter closes the ten-counter clock faster than any lone attacker could. The enters-the-battlefield dig sharpens that plan by digging five deep and refilling the hand with fodder, so the lord replaces itself and its army in one motion. What keeps the design from running away is the shape of the threat it builds: individual Rats stay small, toxic 1 is a slow drip on its own, and the poison total accumulates through combat that the opponent can block and trade away. The King asks you to go wide and stay wide, spending cards on bodies that each contribute a sliver of the win condition, rather than protecting a single haymaker. It sits at the intersection of two archetypes that rarely overlap cleanly (go-wide creature aggression and poison), and its job is to make the two the same deck.