Nim Deathmantle, Phyrexian Altar, and Knight of the Last Breath

Prerequisites

• Nim Deathmantle on the battlefield
• Phyrexian Altar on the battlefield
• Knight of the Last Breath on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing Knight of the Last Breath, adding
2. When Knight of the Last Breath dies, its afterlife ability and Nim Deathmantle trigger
3. Resolve the Knight of the Last Breath trigger, creating three 1/1 Spirit creature tokens
4. Activate Phyrexian Altar three times by sacrificing the Spirits, adding
5. Resolve the Nim Deathmantle trigger from step 2, causing you to pay to return Knight of the Last Breath 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