Smaug the Impenetrable + Metalwork Colossus + Blasting Station + Jolene, the Plunder Queen

Smaug the Impenetrable

Metalwork Colossus

Blasting Station

Jolene, the Plunder Queen

How it works

1. Activate Blasting Station by tapping it and sacrificing Metalwork Colossus, dealing 1 damage to Smaug.
2. Smaug triggers, creating two artifact tokens due to Jolene.
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. When Metalwork Colossus enters, Blasting Station triggers, untapping Blasting Station.
6. Repeat.

This explosive engine uses Blasting Station as both the sacrificial outlet and the damage source, turning every iteration into a loop by dealing noncombat damage to Smaug the Impenetrable. Because Jolene, the Plunder Queen is on the battlefield, that damage causes extra Treasures to be generated, which provides the exact fodder needed to pay Metalwork Colossus's recursion cost and return it straight from the graveyard. You can then recast Metalwork Colossus for free thanks to the cost-reduction ability built right into its oracle text, which conveniently triggers Blasting Station to untap and do it all over again.