Yahenni, Undying Partisan, and Bioengineered Future

Prerequisites

• Yahenni, Undying Partisan on the battlefield
• Bioengineered Future on the battlefield

Steps

1. Activate Yahenni 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 Yahenni ability
5. Repeat

Results

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