Long Feng, Grand Secretariat, and Phantom Train

Prerequisites

• Long Feng, Grand Secretariat on the battlefield
• Phantom Train on the battlefield

Steps

1. Activate Phantom Train by sacrificing a persist creature that doesn't have a -1/-1 counter on it
2. When the creature dies, its persist ability and Long Feng trigger
3. Resolve the Long Feng trigger, putting a +1/+1 counter on the other persist creature
4. Resolve the persist trigger, returning the creature from your graveyard to the battlefield with a -1/-1 counter on it
5. Resolve the Phantom Train ability
6. Repeat

Results

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