Reincarnation, Dualcaster Mage, and Yahenni, Undying Partisan

Prerequisites

• Reincarnation in hand
• Dualcaster Mage in hand
• Yahenni, Undying Partisan on the battlefield
• available

Steps

1. Cast Reincarnation by paying its mana cost
2. Holding priority, cast Dualcaster Mage by paying its mana cost
3. When Dualcaster Mage enters, it triggers, copying Reincarnation, with the copy targeting Dualcaster Mage
4. Resolve the copy of Reincarnation
5. Holding priority, activate Yahenni by sacrificing Dualcaster Mage
6. When Dualcaster Mage dies, Reincarnation triggers, returning Dualcaster Mage from your graveyard to the battlefield
7. Repeat from step 3
8. Resolve all Yahenni abilities from step 5

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite magecraft triggers