Wall of Bone is a uncommon Creature — Skeleton Wall card from Duel Decks: Garruk vs. Liliana (DDD), collector number 41. Current market price: $0.31, TCGplayer market prices via Scryfall.
Defender (This creature can't attack.) {B}: Regenerate this creature. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)