Smaug the Impenetrable + Metalwork Colossus + Goblin Bombardment + Worldwalker Helm

Smaug the Impenetrable

Metalwork Colossus

Goblin Bombardment

Worldwalker Helm

How it works

1. Activate Goblin Bombardment by sacrificing Metalwork Colossus, dealing 1 damage to Smaug.
2. Smaug triggers, creating two artifact tokens due to Worldwalker Helm.
3. Activate Metalwork Colossus by sacrificing the two artifact tokens, returning Metalwork Colossus from your graveyard to your hand.
4. Cast Metalwork Colossus by paying 0.
5. Repeat.

This clever loop starts by using Goblin Bombardment to fling Metalwork Colossus straight at Smaug the Impenetrable, pinging our favorite dragon for 1 noncombat damage. Because Smaug the Impenetrable is indestructible, it survives the blast and triggers to create Treasure tokens, whose output is amplified into extra Map tokens thanks to Worldwalker Helm. Those newly forged tokens then pay the exact sacrifice cost needed to bring Metalwork Colossus looping right back from the graveyard to your hand. Best of all, because the mana value of your noncreature artifacts keeps your casting costs entirely free, you can replay Metalwork Colossus for zero mana and repeat the slaughter indefinitely!