Umbral Collar Zealot, and Bioengineered Future

Prerequisites

• Umbral Collar Zealot on the battlefield
• Bioengineered Future 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 and at least one +1/+1 counter on it due to Bioengineered Future
3. Remove a -1/-1 counter and a +1/+1 counter from that creature as a state-based action
4. Resolve the Umbral Collar Zealot ability
5. Repeat

Results

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