Shepherd of the Cosmos, Phantom Train, and Changing Loyalty

Prerequisites

• Shepherd of the Cosmos on the battlefield
• Phantom Train on the battlefield
• Changing Loyalty on the battlefield

Steps

1. Activate Phantom Train 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 Phantom Train ability Repeat

Results

• Infinite +1/+1 counters on a creature
• Infinite ETB
• Infinite LTB
• Infinite death triggers
• Infinite sacrifice triggers