Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight, and Thermopod

Prerequisites

• Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight on the battlefield
• Thermopod on the battlefield

Steps

1. Activate Thermopod by sacrificing the undying creature
2. When the creature dies, its undying ability triggers, returning the creature from your graveyard to the battlefield with a +1/+1 counter on it
3. Activate Thermopod by sacrificing the undying creature
4. When the creature dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
5. Repeat

Results

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