Mana Vault is a mythic Artifact card from Ultimate Masters (UMA), collector number 229. Current market price: $112.40 (foil $165.19), TCGplayer market prices via Scryfall.
This artifact doesn't untap during your untap step. At the beginning of your upkeep, you may pay {4}. If you do, untap this artifact. At the beginning of your draw step, if this artifact is tapped, it deals 1 damage to you. {T}: Add {C}{C}{C}.