Force Bubble

The depletion counter is the wrinkle that makes this work, and it works by total replacement: any damage that would hit your life total becomes counters on the enchantment instead, so while the bubble is up you take zero. The counter pile is a damage budget, plain and simple. Counters accrue equal to the damage replaced, one per point, and the moment four or more have piled up the enchantment sacrifices itself, leaving you exposed until you can rebuild the wall. That gives the bubble a clean ceiling: three points of damage in a turn slips under the threshold; four or more in a single window blows it open. Crucially, this is a replacement effect, so a single large hit is converted to counters in full before the sacrifice trigger ever resolves: an eight-damage swing becomes eight counters, you take none of it, and only the next source connects, after the enchantment is already gone. The end-step reset is what keeps the floor from caving under attrition: counters clear every turn, so a deck pecking for two or three never crosses the line, while a burst that stacks four in one turn breaks through and forces a redeploy. It draws on the same wear-out accounting that fading and cumulative-upkeep cards used in this era, repurposing a timer mechanic into a damage meter. It reads combat and noncombat sources identically, treating an attacker and a burn spell as the same kind of pressure, which makes it a tidy answer to focused damage and a leaky one against board states that hit from several angles at once.