Yahenni, Undying Partisan, and Warden of the Grove

Prerequisites

• Yahenni, Undying Partisan on the battlefield
• Warden of the Grove 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
3. When the persist creature enters, Warden of the Grove triggers, putting a +1/+1 counter on the persist creature
4. Resolve the Yahenni ability
5. Repeat

Results

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