Toph, the First Metalbender, Magus of the Candelabra, Thousand-Year Elixir, and Regal Behemoth

Prerequisites

• Toph, the First Metalbender on the battlefield
• Magus of the Candelabra on the battlefield
• Thousand-Year Elixir on the battlefield
• Regal Behemoth on the battlefield

Steps

1. Activate three lands by tapping them, adding at least
2. Regal Behemoth triggers three times, adding Activate Magus of the Candelabra by paying and tapping it, untapping the three mana-producing lands and Thousand-Year Elixir, as it's a land due to Toph
3. Activate Thousand-Year Elixir by paying and tapping it, untapping Magus of the Candelabra
4. Repeat

Results

• Infinite mana lands you control can produce
• Infinite mana nontoken artifacts you control can produce
• Infinite untap of lands you control
• Infinite untap of nontoken artifacts you control