Iridescent Drake, Unhallowed Pact, and Phyrexian Altar

Prerequisites

• Iridescent Drake on the battlefield
• Unhallowed Pact on the battlefield
• Phyrexian Altar on the battlefield
• Unhallowed Pact attached to Iridescent Drake

Steps

1. Activate Phyrexian Altar by sacrificing Iridescent Drake, adding one mana of any color
2. When Iridescent Drake dies, Unhallowed Pact triggers, returning Iridescent Drake from your graveyard to the battlefield
3. When Iridescent Drake enters the battlefield, it triggers, returning Unhallowed Pact from your graveyard to the battlefield attached to Iridescent Drake
4. Repeat

Results

• Infinite colored mana
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers