Mirrodin Besieged + Myr Retriever + Scrap Trawler + Ashnod's Altar

Mirrodin Besieged

Myr Retriever

Scrap Trawler

Ashnod's Altar

How it works

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

This clever recursive loop relies on Ashnod's Altar to continuously sacrifice your artifact creatures into a steady stream of colorless mana. As Scrap Trawler and Myr Retriever trade places going to and from the graveyard, Scrap Trawler's ability steps in to let the dying Retriever fish its partner back out, perfectly bridging the mana gap to recast them both. Meanwhile, Mirrodin Besieged watches the loop unfold—choosing the Mirran path lets it flood the board with an endless army of Myr tokens every time an artifact is cast, or the Phyrexian side can quickly push you toward alternative win conditions.