Arni Metalbrow + Thousand-Faced Shadow + Cloudstone Curio + Dockside Extortionist

Arni Metalbrow

Thousand-Faced Shadow

Cloudstone Curio

Dockside Extortionist

How it works

1. Declare Dockside Extortionist as an attacker.
2. Arni Metalbrow triggers, causing you to pay 1 to put Thousand-Faced Shadow from your hand onto the battlefield tapped and attacking.
3. When Thousand-Faced Shadow enters the battlefield, it, Arni Metalbrow and Cloudstone Curio trigger.
4. Resolve the Cloudstone Curio trigger, choosing to return nothing to your hand from the battlefield.
5. Resolve the Arni Metalbrow trigger, choosing not to pay.
6. Resolve the Thousand-Faced Shadow trigger, creating a token copy of Dockside Extortionist that enters the battlefield tapped and attacking.
7. When the Dockside Extortionist token enters the battlefield, it, Arni Metalbrow and Cloudstone Curio trigger.
8. Resolve the Dockside Extortionist trigger, creating at least two Treasure tokens.
9. Activate two Treasures by tapping and sacrificing them, adding 1.
10. Resolve the Cloudstone Curio trigger, returning Thousand-Faced Shadow to your hand from the battlefield.
11. Resolve the Arni Metalbrow trigger, causing you to pay 1 to put Thousand-Faced Shadow from your hand onto the battlefield tapped and attacking.
12. Repeat from step 3.

This clever loop relies on Arni Metalbrow to launch Thousand-Faced Shadow straight into the fray from your hand whenever a creature attacks, while Cloudstone Curio stands ready to bounce the ninja right back to your hand using the creature type shared with the incoming token copy. Every iteration is fueled by Dockside Extortionist (and its generated token copy), which supplies the requisite Treasures to pay the mana costs required to keep Arni Metalbrow's attack trigger firing. As long as your opponents control enough artifacts and enchantments to net at least two Treasures per cycle, you can endlessly repeat the process for an unstoppable wave of attacking tokens and resources.