Toph, the First Metalbender, Spawning Pit, and Biotransference

Prerequisites

• Toph, the First Metalbender on the battlefield
• Spawning Pit on the battlefield
• Biotransference on the battlefield

Steps

1. Cast the earthbend creature by paying its mana cost
2. When the creature enters, it triggers, earthbending the creature, as it's an artifact due to Biotransference, thus making it also a land due to Toph
3. Activate Spawning Pit by sacrificing the earthbent creature
4. When the creature dies, it triggers, returning it from your graveyard to the battlefield tapped
5. When the creature enters, it triggers, earthbending the creature, as it's an artifact due to Biotransference, thus making it also a land due to Toph
6. Resolve the Spawning Pit ability, putting a charge counter on Spawning Pit
7. Repeat from step 3

Results

• Infinite artifact ETB
• Infinite artifact LTB
• Infinite artifact sacrifice triggers
• Infinite charge counters on a permanent
• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers
• Infinite death triggers
• Infinite landfall triggers