Yahenni, Undying Partisan, Fiend Hunter, and Hero of the Dunes

Prerequisites

• Yahenni, Undying Partisan on the battlefield
• Fiend Hunter in hand
• Hero of the Dunes on the battlefield
• available

Steps

1. Cast Fiend Hunter by paying its mana cost
2. When Fiend Hunter enters, its first ability triggers, exiling Hero of the Dunes
3. Activate Yahenni by sacrificing Fiend Hunter
4. When Fiend Hunter dies, its second ability triggers, returning Hero of the Dunes from exile to the battlefield
5. When Hero of the Dunes enters, it triggers, returning Fiend Hunter from your graveyard to the battlefield
6. When Fiend Hunter enters, its first ability triggers, exiling Hero of the Dunes
7. Resolve the Yahenni ability
8. Repeat from step 3

Results

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