Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight, Altar of Dementia, and Spiteful Squad

Prerequisites

• Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight on the battlefield
• Altar of Dementia on the battlefield
• Spiteful Squad on the battlefield

Steps

1. Activate Altar of Dementia by sacrificing Spiteful Squad
2. When Spiteful Squad dies, its persist ability triggers, returning it from your graveyard to the battlefield without a -1/-1 counter on it due to its replacement effect
3. Resolve the Altar of Dementia ability
4. Repeat

Results

• Infinite +1/+1 counters on creatures you control
• Infinite ETB
• Infinite LTB
• Infinite death triggers
• Infinite mill
• Infinite recursion of creatures you control
• Infinite sacrifice triggers
• Infinite self-mill