Devour in Shadow

The price is the whole transaction: kill anything, no toughness cap, no regeneration loophole, and pay for it out of your own life total in proportion to what you killed. Where most unconditional black removal of this era charged a stiff mana cost or carved out exceptions (the color restrictions and "can't target black" clauses that hedged the era's cheap kill spells), this one keeps the mana commitment to two black and converts the missing rate into life loss scaled to the threat. That makes it a clean answer to a small evasive creature and a genuine gamble against a fattened-up beater: removing a seven-toughness monster costs you seven life, a swing that can decide a race even when the removal itself resolves perfectly. Pegging the cost to toughness rather than power is the sharp choice, since it charges you most for the durable wall-shaped blockers you most want gone while letting you cheaply dispatch a fragile attacker. The regeneration clause matters because this is a targeted destroy effect, the lineage that left regeneration open where edict-style sacrifice answers never did; it shuts the door that Terror and the older "destroy target creature" spells left ajar. The result is reliable where reliability counts: you get any creature that can be destroyed, and the only open question is what keeping it dead costs you.