Saffi Eriksdotter, Extraction Specialist, and Phyrexian Altar

Prerequisites

• Saffi Eriksdotter on the battlefield
• Extraction Specialist on the battlefield
• Phyrexian Altar on the battlefield

Steps

1. Activate Saffi by sacrificing it, targeting Extraction Specialist
2. Activate Phyrexian Altar by sacrificing Extraction Specialist, adding one mana of any color
3. When Extraction Specialist dies, Saffi triggers, returning Extraction Specialist from your graveyard to the battlefield
4. When Extraction Specialist enters the battlefield, it triggers, returning Saffi from your graveyard to the battlefield
5. Repeat

Results

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