Adarkar Valkyrie, Sparring Mummy, and Phyrexian Altar

Prerequisites

• Adarkar Valkyrie on the battlefield
• Sparring Mummy on the battlefield
• Phyrexian Altar on the battlefield

Steps

1. Activate Adarkar Valkyrie by tapping it, making it so the next time Sparring Mummy dies this turn it will be returned to the battlefield
2. Activate Phyrexian Altar by sacrificing Sparring Mummy, adding one mana of any color
3. Adarkar Valkyrie triggers, returning Sparring Mummy to the battlefield
4. Sparring Mummy enters the battlefield, untapping Adarkar Valkyrie
5. Repeat

Results

• Infinite colored mana
• Infinite death triggers
• Infinite creature ETB
• Infinite creature LTB
• Infinite creature sacrifice triggers