Welding Jar
Free protection, sold in a single sacrifice. Costing nothing to cast and nothing to hold, it sits on the battlefield as a one-shot insurance policy: when a removal spell or board wipe points at the artifact you actually care about, you crack this in response and the target survives. Regenerate is the mechanic doing the work, and it is worth being precise about: the artifact never leaves the battlefield. Instead it taps, sheds any marked damage, and is removed from combat if it was fighting, which means it holds onto its auras, counters, and equipment through the whole exchange. The zero cost is the whole pitch. A card that demands no mana to deploy never asks you to skip a real play to set up the defense; it just waits, already paid for, until the moment arrives. The regenerate clause carries its own quiet limits, though, because regeneration only answers destruction. It does nothing against a sacrifice effect, a counterspell, or any removal that exiles rather than destroys, so it covers the most common forms of artifact removal and nothing more exotic. That narrowness is why artifact-heavy strategies have always treated it as cheap, expendable backup rather than a centerpiece: for a game plan that hinges on one key artifact surviving a turn, a free regenerator earns its slot precisely because running it never costs you anything to find out whether you needed it.
