Woodfall Primus, Yahenni, Undying Partisan, and Hardened Academic

Prerequisites

• Woodfall Primus on the battlefield
• Yahenni, Undying Partisan on the battlefield
• Hardened Academic on the battlefield

Steps

1. Activate Yahenni by sacrificing Woodfall Primus
2. When Woodfall Primus dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it
3. Hardened Academic and Woodfall Primus trigger
4. Resolve the Hardened Academic trigger, putting a +1/+1 counter on Woodfall Primus
5. Resolve the Woodfall Primus trigger, destroying target noncreature permanent
6. Resolve the Yahenni ability Repeat

Results

• Destroy any number of noncreature permanents
• Infinite ETB
• Infinite LTB
• Infinite death triggers
• Infinite sacrifice triggers
• Lock