Carrion Feeder, and Railway Brawler

Prerequisites

• Carrion Feeder on the battlefield
• Railway Brawler on the battlefield

Steps

1. Activate Carrion Feeder by sacrificing the persist creature
2. When the persist creature dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
3. When the persist creature enters, Railway Brawler triggers, putting a number of +1/+1 counters on the persist creature
4. Resolve the Carrion Feeder ability
5. Repeat

Results

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