Mana Vault

{t} Add 3 colorless mana to your mana pool.
Mana Vault doesn’t untap normally during
untap phase; to untap it, you must pay 4 mana
during your upkeep. If Mana Vault remains
tapped during upkeep it deals 1 damage to you.
Drawing mana from this artifact is played as an interrupt.
The life of the old forgotten king lingers long into his confinement, a source of power for his crazed jailer.