Mikaeus, the Unhallowed, Deathbringer Thoctar, and Altar of Dementia

Prerequisites

• Mikaeus, the Unhallowed on the battlefield
• Deathbringer Thoctar on the battlefield
• Altar of Dementia on the battlefield

Steps

1. Activate Deathbringer Thoctar by removing a +1/+1 counter from it, dealing 1 damage to any target
2. Repeat step 1 until Deathbringer Thoctar has no +1/+1 counters on it
3. Activate Altar of Dementia by sacrificing Deathbringer Thoctar
4. Deathbringer Thoctar dies, triggering its undying ability, returning it from your graveyard to the battlefield with a +1/+1 counter on it
5. Resolve the Altar of Dementia ability, causing target player to mill cards equal to Deathbringer Thoctar's power
6. Repeat

Results

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