Szarel, Genesis Shepherd, Crystalline Crawler, Slimefoot and Squee, and Umbral Collar Zealot

Prerequisites

• Szarel, Genesis Shepherd on the battlefield
• Crystalline Crawler on the battlefield
• Slimefoot and Squee on the battlefield
• Umbral Collar Zealot on the battlefield

Steps

1. Activate Umbral Collar Zealot twice by sacrificing Slimefoot and Squee and another nontoken creature
2. When the creatures are sacrificed, Szarel triggers twice, putting a number of +1/+1 counters equal to twice Szarel's power on Crystalline Crawler
3. Resolve the Umbral Collar Zealot abilities
4. Activate Crystalline Crawler four times by removing four +1/+1 counters from it, adding
5. Activate Slimefoot and Squee by paying and sacrificing a Saproling, returning it and another creature from your graveyard to the battlefield
6. When Slimefoot and Squee enters, it triggers, creating a 1/1 Saproling creature token
7. Repeat

Results

• Infinite LTB
• Infinite ETB
• Infinite colored mana
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite +1/+1 counters
• Infinite surveil 1
• Infinite recursion of creature cards in your graveyard