Smaug the Impenetrable + Metalwork Colossus + Doubling Season + Goblin Bombardment

Smaug the Impenetrable

Metalwork Colossus

Doubling Season

Goblin Bombardment

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 Doubling Season.
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 loop turns the legendary dragon Smaug the Impenetrable into an explosive engine for infinite sacrifice and artifact triggers. By using Goblin Bombardment to deal noncombat damage to Smaug, you trigger his ability to generate Treasure tokens—a payout immediately doubled by Doubling Season's replacement effect. Those very same tokens then serve as the sacrifice fodder to fuel Metalwork Colossus's recursion ability, returning the massive automaton from your graveyard to your hand. Because Metalwork Colossus's cost reduction scales with your noncreature artifacts (and the returning treasures help feed future loops), you can recast it for free and feed it back into Goblin Bombardment to repeat the whole sequence indefinitely.