Lesser Masticore, Phantom Train, and Hardened Academic

Prerequisites

• Lesser Masticore on the battlefield
• Phantom Train on the battlefield
• Hardened Academic on the battlefield

Steps

1. Activate Phantom Train by sacrificing Lesser Masticore
2. When Lesser Masticore dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
3. Hardened Academic triggers, putting a +1/+1 counter on Lesser Masticore
4. Resolve the Phantom Train ability
5. Repeat

Results

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