Boneyard Scourge, Molten Echoes, and Phyrexian Altar

Prerequisites

• Boneyard Scourge on the battlefield
• Molten Echoes on the battlefield
• Phyrexian Altar on the battlefield
• You control at least one additional Dragon
• "Dragon" chosen with Molten Echoes

Steps

1. Activate Phyrexian Altar by sacrificing Boneyard Scourge, adding
2. Activate Phyrexian Altar by sacrificing another Dragon, adding
3. When the Dragon dies, Boneyard Scourge triggers, causing you to pay to return it from your graveyard to the battlefield
4. When Boneyard Scourge enters the battlefield, Molten Echoes triggers, creating a token copy of Boneyard Scourge with haste
5. Repeat

Results

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