Wall of Bone

Alpha's defender walls gave several colors a defensive creature, and this was one of black's: the only one with a built-in survival clause. Where Wall of Wood and Wall of Swords just sat there, this one could pay a black mana to shrug off a removal spell or a combat trade and come back tapped, a then-novel pairing of the regenerate keyword with a body designed to eat damage rather than deal it. The design logic is tidy: black does not get cheap large toughness for free, so the toughness is small (a 1/4 rather than the cycle's chunkier walls) and the durability is rented from the same color that wants to spend mana on discard and removal anyway. That tension, between holding up regeneration mana and casting a real spell, is the whole tax the card charges. Regenerate has since been largely retired from new design in favor of indestructible and "if it would die, exile it instead" clauses, which makes this a small museum piece: a defensive creature that costs ongoing resources to keep alive rather than a static wall that simply exists. The skeleton typing and the gothic art slot it into the same Alpha vocabulary as Drudge Skeletons, which runs the same regenerate-for-black trick on an attacker.