Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight, Ashnod's Altar, and Ceti Eel

Prerequisites

• Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight on the battlefield
• Ashnod's Altar on the battlefield
• Ceti Eel on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing Ceti Eel
2. When Ceti Eel dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
3. When Ceti Eel enters, it triggers, causing you to mill two cards and put a +1/+1 counter on it
4. Repeat

Results

• Infinite colorless mana
• Infinite creature ETB
• Infinite creature LTB
• Infinite death triggers
• Infinite creature sacrifice triggers
• Infinite self-mill