Restless Apparition, Yahenni, Undying Partisan, and Hardened Academic

Prerequisites

• Restless Apparition on the battlefield
• Yahenni, Undying Partisan on the battlefield
• Hardened Academic on the battlefield

Steps

1. Activate Yahenni by sacrificing Restless Apparition
2. When Restless Apparition dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
3. Hardened Academic triggers, putting a +1/+1 counter on Restless Apparition
4. Resolve the Yahenni ability
5. Repeat

Results

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