Shepherd of the Cosmos, Phantom Train, and Necrogen Communion

Prerequisites

• Shepherd of the Cosmos on the battlefield
• Phantom Train on the battlefield
• Necrogen Communion on the battlefield

Steps

1. Activate Phantom Train by sacrificing Shepherd of the Cosmos
2. When Shepherd of the Cosmos dies, Necrogen Communion triggers, returning Shepherd of the Cosmos from your graveyard to the battlefield
3. When Shepherd of the Cosmos enters the battlefield, it triggers, returning Necrogen Communion from your graveyard to the battlefield attached to Shepherd of the Cosmos
4. Resolve the Phantom Train ability, putting a +1/+1 counter on it
5. Repeat

Results

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