Nim Deathmantle, Ashnod's Altar, and Pestbrood Sloth

Prerequisites

• Nim Deathmantle on the battlefield
• Ashnod's Altar on the battlefield
• Pestbrood Sloth on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing Pestbrood Sloth, adding
2. When Pestbrood Sloth dies, it and Nim Deathmantle trigger, Resolve the Pestbrood Sloth trigger, creating two creature tokens
3. Holding priority, activate Ashnod's Altar by sacrificing a creature token, adding
4. Resolve the Nim Deathmantle trigger, causing you to pay to return Pestbrood Sloth from your graveyard to the battlefield and attach Nim Deathmantle to it
5. Repeat

Results

• Infinite ETB
• Infinite LTB
• Infinite colorless mana
• Infinite death triggers
• Infinite sacrifice triggers
• Infinite creature tokens