Nim Deathmantle, Ashnod's Altar, and Penumbra Spider

Prerequisites

• Nim Deathmantle on the battlefield
• Ashnod's Altar on the battlefield
• Penumbra Spider on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing Penumbra Spider, adding
2. When Penumbra Spider dies, it and Nim Deathmantle triggers
3. Resolve the Penumbra Spider trigger, creating a 2/4 Spider creature token
4. Activate Ashnod's Altar by sacrificing the Spider, adding
5. Resolve the Nim Deathmantle trigger from step 2, causing you to pay to return Penumbra Spider from your graveyard to the battlefield, and attach Nim Deathmantle to it
6. Repeat

Results

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