Ashnod's Altar, Dualcaster Mage, and Graceful Reprieve

Prerequisites

• Ashnod's Altar on the battlefield
• Dualcaster Mage in hand
• Graceful Reprieve in hand
• available

Steps

1. Cast Graceful Reprieve by paying its mana cost
2. Holding priority, cast Dualcaster Mage by paying its mana cost
3. When Dualcaster Mage enters, it triggers, copying Graceful Reprieve, with the copy targeting Dualcaster Mage
4. Resolve the copy of Graceful Reprieve
5. Holding priority, activate Ashnod's Altar by sacrificing Dualcaster Mage
6. When Dualcaster Mage dies, Graceful Reprieve triggers, returning Dualcaster Mage from your graveyard to the battlefield
7. Repeat from step 3

Results

• Infinite creature LTB
• Infinite creature ETB
• Infinite creature sacrifice triggers
• Infinite death triggers
• Infinite colorless mana
• Infinite magecraft triggers