Barrin, Master Wizard + Myr Battlesphere + Krark-Clan Ironworks + Elesh Norn, Mother of Machines

Barrin, Master Wizard

Myr Battlesphere

Krark-Clan Ironworks

Elesh Norn, Mother of Machines

How it works

1. Cast Myr Battlesphere by paying 7.
2. When Myr Battlesphere enters the battlefield, it triggers twice, creating eight 1/1 Myr artifact creature tokens.
3. Activate Krark-Clan Ironworks five times by sacrificing five Myrs, adding ten C.
4. Activate Barrin by paying 2 and sacrificing a Myr, returning Myr Battlesphere to your hand from the battlefield.
5. Repeat.

This loop relies on Elesh Norn, Mother of Machines to double up the entry trigger of Myr Battlesphere, flooding your board with eight Myr tokens instead of the usual four. You then feed those tokens and the Battlesphere itself into Krark-Clan Ironworks to generate the massive amounts of colorless mana required to keep the engine running. Finally, Barrin, Master Wizard acts as your recurring bounce outlet, spending that mana and a leftover artifact to return the Battlesphere to your hand so you can recast it and start the cycle anew.