Nim Deathmantle, Ashnod's Altar, and Catacomb Sifter

Prerequisites

• Nim Deathmantle on the battlefield
• Ashnod's Altar on the battlefield
• Catacomb Sifter on the battlefield
• available

Steps

1. Activate Ashnod's Altar by sacrificing Catacomb Sifter, adding
2. When Catacomb Sifter dies, Nim Deathmantle triggers, causing you to pay to return Catacomb Sifter from your graveyard to the battlefield and attach Nim Deathmantle to it
3. When Catacomb Sifter enters, it triggers, creating a creature token
4. Activate Ashnod's Altar by sacrificing a creature token, adding
5. Repeat

Results

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