Headless Rider, Nim Deathmantle, and Ashnod's Altar

Prerequisites

• Headless Rider on the battlefield
• Nim Deathmantle on the battlefield
• Ashnod's Altar on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing Headless Rider, adding
2. Headless Rider and Nim Deathmantle trigger
3. Resolve the Headless Rider trigger, creating a 2/2 Zombie creature token
4. Activate Ashnod's Altar by sacrificing the Zombie token, adding
5. Resolve the Nim Deathmantle trigger, paying to return Headless Rider to the battlefield, and attach Nim Deathmantle to it
6. Repeat

Results

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