Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight, Shilgengar, Sire of Famine, and Ceti Eel

Prerequisites

• Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight on the battlefield
• Shilgengar, Sire of Famine on the battlefield
• Ceti Eel on the battlefield

Steps

1. Activate Shilgengar 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. Resolve the Shilgengar ability
5. Repeat

Results

• Infinite Blood tokens
• Infinite creature ETB
• Infinite creature LTB
• Infinite death triggers
• Infinite creature sacrifice triggers
• Infinite artifact tokens
• Infinite self-mill