Umbral Collar Zealot, and Railway Brawler

Prerequisites

• Umbral Collar Zealot on the battlefield
• Railway Brawler on the battlefield

Steps

1. Activate Umbral Collar Zealot 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 Umbral Collar Zealot ability
5. Repeat

Results

• Infinite ETB
• Infinite LTB
• Infinite death triggers
• Infinite sacrifice triggers
• Infinite surveil