Saffi Eriksdotter, Karmic Guide, and Phyrexian Altar

Prerequisites

• Saffi Eriksdotter on the battlefield
• Karmic Guide on the battlefield
• Phyrexian Altar on the battlefield

Steps

1. Activate Saffi by sacrificing it, targeting Karmic Guide
2. Activate Phyrexian Altar by sacrificing Karmic Guide, adding one mana of any color
3. Karmic Guide dies, triggering Saffi, returning Karmic Guide from your graveyard to the battlefield
4. When Karmic Guide 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