Stalwart Successor, Umbral Collar Zealot, and Gravelgill Axeshark

Prerequisites

• Stalwart Successor on the battlefield
• Umbral Collar Zealot on the battlefield
• Gravelgill Axeshark on the battlefield

Steps

1. Activate Umbral Collar Zealot by sacrificing Gravelgill Axeshark When Gravelgill Axeshark dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
2. When Gravelgill Axeshark enters, Stalwart Successor triggers, putting a +1/+1 counter on Gravelgill Axeshark Resolve the Umbral Collar Zealot ability
3. Repeat

Results

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