Morophon, the Boundless, Saffi Eriksdotter, Eternal Witness, and Ashnod's Altar

Prerequisites

• Morophon, the Boundless on the battlefield
• Saffi Eriksdotter on the battlefield
• Eternal Witness on the battlefield
• Ashnod's Altar on the battlefield
• "Human" or "Scout" chosen with Morophon

Steps

1. Activate Saffi by sacrificing it, targeting Eternal Witness
2. Activate Ashnod's Altar by sacrificing Eternal Witness, adding
3. When Eternal Witness dies, Saffi triggers, returning it from your graveyard to the battlefield
4. When Eternal Witness enters the battlefield, it triggers, returning Saffi from your graveyard to your hand
5. Cast Saffi by paying due to Morophon
6. Repeat

Results

• Infinite colorless mana
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers
• Infinite storm count