Yarus, Roar of the Old Gods, Master of the Veil, and Altar of Dementia

Prerequisites

• Yarus, Roar of the Old Gods on the battlefield
• Master of the Veil on the battlefield
• Altar of Dementia on the battlefield

Steps

1. Activate Altar of Dementia by sacrificing Master of the Veil
2. When Master of the Veil dies, Yarus' second ability triggers, returning Master of the Veil from your graveyard to the battlefield face down, then turning it face up
3. Master of the Veil triggers, turning itself face down
4. Resolve the Altar of Dementia ability, causing target player to mill cards equal to Master of the Veil's power
5. Repeat

Results

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