Phyrexian Totem

The mana rock that fights back, and gets you killed if it loses. The five color totems share one skeleton: tap for a color, pay to animate into a body, then pay a price whenever damage lands. But where the others shatter outright the moment they take a hit (their damage clause is a death sentence), this one keeps the body and bills you elsewhere. Animated, it is a 5/5 trampler that arrives for two and a black mana, durable enough to survive most combat. The penalty is what disciplines the math: take damage as a creature and you sacrifice that many permanents, so a clean trade with a 4/4 leaves the Horror standing while four of your own permanents feed the maw. The design captures Phyrexia's whole ethos in a downside clause: power without compunction, paid in your own resources. As a mana source it is pure, a colorless permanent that produces black and sits idle until you need a beater. The animation cost makes that beater cheap; the sacrifice clause makes it dangerous to use carelessly. You swing it into open ground or for the last few points of damage, not to trade, because trading is precisely how it eats your board. The clause is self-correcting in a way the era's do-it-all artifacts rarely bothered with, punishing the greedy line at the exact moment a player reaches for it, so the thing ramps early and threatens late without ever being free to throw away.