Magus of the Coffers + Staff of Domination

Magus of the Coffers
Staff of Domination

Requires
Magus of the Coffers must be on the battlefield. Staff of Domination must be on the battlefield. Magus of the Coffers is not summoning sick and can tap for mana. At least seven Swamps under your control. 2 to start the combo.
Steps
  1. Pay 2 to activate Magus of the Coffers, adding at least seven b.
  2. Pay 3 to activate Staff of Domination's third ability, untapping Magus of the Coffers.
  3. Pay 1 to activate Staff of Domination's first ability, untapping itself.
  4. Repeatedly tap the Magus for mana and untap it, generating at least b per iteration.
Results
Infinite black mana.