Spawning Pit, Dualcaster Mage, and Makeshift Mannequin

Prerequisites

• Spawning Pit 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 Spawning Pit by sacrificing Dualcaster Mage, putting a charge counter on Spawning Pit
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 charge counters on a permanent
• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers
• Infinite death triggers
• Infinite magecraft triggers