Caustic Hound

The death trigger fires symmetrically, and that symmetry is the whole design problem. Four life from each player on death sounds like a wash, but the math only works for the controller if the life totals are already lopsided or if a sacrifice outlet turns the trigger into a deliberate finisher rather than a combat accident. As a 4/4 for six, the body is a deliberate underpay: nothing about the rate is meant to win the game, because the card's payload sits entirely in what happens when it dies. That makes it a creature whose owner wants it dead, which inverts the usual relationship between blocking and survival; trading it away in combat is closer to casting a burn spell at both players than losing a creature. The Phyrexian flavor frames the drain as contagion that does not discriminate, and the design follows the flavor: this is not a drain effect like Gray Merchant of Asphodel that quietly favors the caster, but a blunt instrument that hurts everyone equally and asks the pilot to have already tilted the race in their favor. It belongs to the lineage of death-trigger payoffs built to be sacrificed rather than attacked with, where the four-life body is just the fuse and the real spell is the explosion.