Mirrodin Besieged, Myr Retriever, Scrap Trawler, and Ashnod's Altar

Prerequisites

• Mirrodin Besieged on the battlefield
• Myr Retriever in the graveyard
• Scrap Trawler on the battlefield
• Ashnod's Altar on the battlefield
• "Mirran" chosen with Mirrodin Besieged

Steps

1. Activate Ashnod's Altar by sacrificing Scrap Trawler, adding
2. When Scrap Trawler dies, it triggers, returning Myr Retriever from your graveyard to your hand
3. Cast Myr Retriever by paying
4. Mirrodin Besieged triggers, creating a 1/1 Myr artifact creature token
5. Activate Ashnod's Altar twice by sacrificing the Myr and Myr Retriever, adding
6. When Myr Retriever dies, it triggers, returning Scrap Trawler from your graveyard to your hand
7. Cast Scrap Trawler by paying
8. Mirrodin Besieged triggers, creating a 1/1 Myr artifact creature token
9. Repeat

Results

• Infinite colorless mana
• Infinite creature tokens
• Infinite death triggers
• Infinite ETB
• Infinite LTB
• Infinite sacrifice triggers
• Infinite storm count