Relentless Dead, Necroduality, and Ashnod's Altar

Prerequisites

• Relentless Dead in hand
• Necroduality on the battlefield
• Ashnod's Altar on the battlefield
• available

Steps

1. Cast Relentless Dead by paying
2. When Relentless Dead enters the battlefield, Necroduality triggers, creating a token copy of it
3. Activate Ashnod's Altar by sacrificing the nontoken Relentless Dead, adding
4. When Relentless Dead dies, its first and second abilities trigger
5. Choose not to pay for either
6. Activate [[FSO]] by sacrificing the token Relentless Dead, adding
7. When the token Relentless Dead dies, its first and second abilities trigger
8. Resolve the first trigger, choosing not to pay
9. Resolve the second trigger, causing you to pay to return Relentless Dead from your graveyard to the battlefield
10. Repeat from step 2

Results

• Infinite LTB
• Infinite ETB
• Infinite sacrifice triggers
• Infinite death triggers
• Infinite colorless mana
• Infinite recursion of Zombie cards in your graveyard