First Day of Class, and Phantom Train

Prerequisites

• First Day of Class in hand
• Phantom Train on the battlefield
• available

Steps

1. Cast First Day of Class by paying
2. Activate Phantom Train by sacrificing the persist creature
3. When the persist creature dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
4. When the persist creature enters, First Day of Class triggers, putting a +1/+1 counter on the persist creature
5. Resolve the Phantom Train ability
6. Repeat from step 2

Results

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