Shepherd of the Cosmos, Yahenni, Undying Partisan, and Changing Loyalty

Prerequisites

• Shepherd of the Cosmos on the battlefield
• Yahenni, Undying Partisan on the battlefield
• Changing Loyalty on the battlefield

Steps

1. Activate Yahenni by sacrificing Shepherd of the Cosmos
2. When Shepherd of the Cosmos dies, Changing Loyalty triggers, returning Shepherd of the Cosmos from your graveyard to the battlefield
3. When Shepherd of the Cosmos enters the battlefield, it triggers, returning Changing Loyalty from your graveyard to the battlefield attached to Shepherd of the Cosmos
4. Resolve the Yahenni ability Repeat

Results

• Infinite creature ETB
• Infinite creature LTB
• Infinite death triggers
• Infinite creature sacrifice triggers