Dualcaster Mage, Extract from Darkness, and Yahenni, Undying Partisan

Prerequisites

• Dualcaster Mage in hand
• Extract from Darkness in hand
• Yahenni, Undying Partisan on the battlefield
• available

Steps

1. Cast Extract from Darkness by paying its mana cost Holding priority, cast Dualcaster Mage by paying its mana cost
2. When Dualcaster Mage enters, it triggers, targeting Extract from Darkness
3. Holding priority, activate Yahenni by sacrificing Dualcaster Mage
4. Resolve the Dualcaster Mage trigger, copying Extract from Darkness Resolve the Extract from Darkness copy, causing each player to mill two cards and returning Dualcaster Mage from your graveyard to the battlefield
5. Repeat from step 3

Results

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