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}.
NM-Mint - $106.20
Lightly Played - $95.60
Moderately Played - $85.00
Heavily Played - $74.30
Damaged - $53.10
NM-Mint Non English - $106.20
Lightly Played Non English - $95.60
Moderately Played Non English - $85.00
Heavily Played Non English - $74.30
Damaged Non English - $53.10