Warbeast of Gorgoroth, Primal Vigor, and Phantom Train

Prerequisites

• Warbeast of Gorgoroth on the battlefield
• Primal Vigor on the battlefield
• Phantom Train on the battlefield

Steps

1. Activate Phantom Train by sacrificing the creature with power 4 or greater
2. When the creature dies, Warbeast of Gorgoroth triggers, creating a 0/0 Army creature token if you don't control one, then putting four +1/+1 counters on an Army you control
3. Resolve the Phantom Train ability, putting a +1/+1 counter on Phantom Train and causing it to become a creature until end of turn Repeat

Results

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