Xathrid Necromancer, Xenograft, and Phantom Train

Prerequisites

• Xathrid Necromancer on the battlefield
• Xenograft on the battlefield
• Phantom Train on the battlefield

Steps

1. Activate Phantom Train by sacrificing any other creature
2. When the creature dies as a Human due to Xenograft, Xathrid Necromancer triggers, creating a 2/2 Zombie creature token
3. Resolve the Phantom Train ability
4. Repeat

Results

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