Sunstone Vault

Sunstone Vault enters the battlefield tapped with
a lock counter on it.
{x}{1}{w}, {t}, Remove a lock counter from Sunstone Vault: You gain two times X life.
{x}{w}, {t}, Sacrifice Sunstone Vault: Exile all nonland permanents with converted mana cost X or less. Activate this ability only if there are no lock counters on Sunstone Vault.