Mana Vault doesn't untap during your untap step.
At the beginning of your upkeep, you may pay {4}. If you do, untap Mana Vault.
At the beginning of your draw step, if Mana Vault is tapped, it deals 1 damage to you.
{T}: Add {C}{C}{C}.
Near Mint - $65.30
Lightly Played - $58.80
Moderately Played - $52.20
Heavily Played - $42.40
Damaged - $29.40
Near Mint French - $65.30
Lightly Played French - $58.80
Moderately Played French - $52.20
Heavily Played French - $42.40
Damaged French - $29.40