Infernal Vessel, Valkyrie's Call, and Ashnod's Altar

Prerequisites

• Infernal Vessel on the battlefield
• Valkyrie's Call on the battlefield
• Ashnod's Altar on the battlefield

Steps

1. Activate Ashnod's Altar by sacrificing Infernal Vessel, adding
2. When Infernal Vessel dies, it triggers, returning itself from your graveyard to the battlefield as a Demon in addition to its other types
3. Activate Ashnod's Altar by sacrificing Infernal Vessel, adding
4. When Infernal Vessel dies, Valkyrie's Call triggers, returning Infernal Vessel from your graveyard to the battlefield as an Angel in additional to its other types
5. Repeat

Results

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