Betrayer's Bargain

Five damage to a creature for two mana is a premium rate for red removal, well past the reach of most instant-speed burn; the additional cost is what balances the ledger. You either feed the spell a creature or an enchantment you were happy to lose, or you buy your way out for , turning the discount into a flat four-mana kill when you have nothing to spare. That optionality is the whole design: sacrifice shells already generate expendable bodies, so the sacrifice line reads as free tempo to them and as a tax to everyone else. The exile clause is where it earns its place against the modern removal-proof crowd. If that creature would die this turn it goes to exile instead, so death-triggers, graveyard recursion, and the ballooning ranks of creatures with "when this dies" payoffs never get to resolve. Note the boundary the clause sets: it only bites when the creature would actually die this turn, so an indestructible creature (which does not die to lethal damage in the first place) simply eats five and shrugs, and the replacement never fires. Five is a deliberately chosen number, big enough to clear the fatties that sit above three-point burn while still leaving certain protected threats out of range. The card sells you efficiency at a price sacrifice decks are already paying anyway, and slams the graveyard door on anything it does manage to kill.