Iridescent Drake, Necrogen Communion, and Phyrexian Altar

Prerequisites

• Iridescent Drake on the battlefield
• Necrogen Communion on the battlefield
• Phyrexian Altar on the battlefield
• Necrogen Communion attached to Iridescent Drake

Steps

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