Pentagram of the Ages

Count the conditions stacked against this thing: four mana to deploy, then four more and a tap to use it, and what you buy is the prevention of a single instance of damage from a single source, aimed at your life total and nothing else. It cannot save a blocker, cannot blank an alpha strike, cannot redirect a burn spell off a creature you care about. A whole board of attackers steps through it untouched while you pay full price to turn aside one of them. A one-mana Healing Salve covers more for a sliver of the outlay, and against the kind of damage that actually threatens a life total directly the activation arrives too slow and too small to register. What it preserves is a snapshot of an unsettled design question. The rate on repeatable damage prevention had not been worked out yet, and the answer here treats your life as the only resource worth a standing shield while charging more per raise than most of the blows it deflects would have cost you in the first place. The narrow targeting is the tell: one source, one instance, your own life, sorcery-tier value at a steep activation. It promises permanence and then prices each use so high that the protection rarely shows up the turn it would have mattered.