Nim Deathmantle, Ashnod's Altar, and Agents of HYDRA

Prerequisites

• Nim Deathmantle on the battlefield
• Ashnod's Altar on the battlefield
• Agents of HYDRA on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing Agents of HYDRA, adding
2. When Agents of HYDRA dies, it and Nim Deathmantle trigger, Resolve the Agents of HYDRA trigger, creating a creature token
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 Agents of HYDRA from your graveyard to the battlefield and attach Nim Deathmantle to it
5. Repeat

Results

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