Mikaeus, the Unhallowed, Chainbreaker, and Altar of Dementia

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Chainbreaker on the battlefield
• Altar of Dementia on the battlefield

Steps

1. Activate Altar of Dementia by sacrificing Chainbreaker
2. Chainbreaker dies, triggering its undying ability, returning it from your graveyard to the battlefield with a -1/-1 counter on it
3. Resolve the Altar of Dementia ability, causing target player to mill cards equal to Chainbreaker's power
4. Repeat

Results

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