Altar of Dementia, Dualcaster Mage, and Makeshift Mannequin

Prerequisites

• Altar of Dementia on the battlefield
• Dualcaster Mage in hand
• Makeshift Mannequin in hand
• available

Steps

1. Cast Makeshift Mannequin by paying its mana cost
2. Holding priority, cast Dualcaster Mage by paying its mana cost
3. When Dualcaster Mage enters, it triggers, targeting Makeshift Mannequin
4. Holding priority, activate Altar of Dementia by sacrificing Dualcaster Mage, causing a player to mill card(s)
5. Resolve the Dualcaster Mage trigger, copying Makeshift Mannequin Resolve the Makeshift Mannequin copy, returning Dualcaster Mage from your graveyard to the battlefield
6. Repeat from step 3

Results

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