Szarel, Genesis Shepherd, Crystalline Crawler, Umbral Collar Zealot, and Gravecrawler

Prerequisites

• Szarel, Genesis Shepherd on the battlefield
• Crystalline Crawler on the battlefield
• Umbral Collar Zealot on the battlefield
• Gravecrawler in the graveyard
• available

Steps

1. Cast Gravecrawler from your graveyard by paying its mana cost
2. Activate Umbral Collar Zealot by sacrificing Gravecrawler
3. When Gravecrawler is sacrificed, Szarel triggers, putting a number of +1/+1 counters equal to Szarel's power on Crystalline Crawler
4. Resolve the Umbral Collar Zealot ability
5. Activate Crystalline Crawler by removing a +1/+1 counter from it, adding
6. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite colored mana
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite storm count
• Infinite +1/+1 counters
• Infinite surveil 1