Shepherd of the Cosmos, Angelic Renewal, and Altar of Dementia

Prerequisites

• Shepherd of the Cosmos on the battlefield
• Angelic Renewal on the battlefield
• Altar of Dementia on the battlefield

Steps

1. Activate Altar of Dementia by sacrificing Shepherd of the Cosmos
2. Shepherd of the Cosmos dies, triggering Angelic Renewal, causing you to sacrifice Angelic Renewal and return Shepherd of the Cosmos from your graveyard to the battlefield
3. Shepherd of the Cosmos enters the battlefield, returning Angelic Renewal from your graveyard to the battlefield
4. Resolve the Altar of Dementia ability, causing target player to mill cards equal to Shepherd of the Cosmos' power
5. Repeat

Results

• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite mill
• Infinite sacrifice triggers
• Infinite self-mill