Toph, the First Metalbender + Toph, Hardheaded Teacher + Rakdos Carnarium + Yahenni, Undying Partisan

Toph, the First Metalbender

Toph, Hardheaded Teacher

Rakdos Carnarium

Yahenni, Undying Partisan

How it works

1. Cast the artifact by paying 0.
2. Toph, Hardheaded Teacher triggers, earthbending Rakdos Carnarium.
3. Resolve the artifact spell.
4. Activate Yahenni by sacrificing Rakdos Carnarium.
5. When Rakdos Carnarium dies, Toph, Hardheaded Teach triggers, returning Rakdos Carnarium from your graveyard to the battlefield tapped.
6. When Rakdos Carnarium enters, it triggers, returning the artifact cast in step 1 from the battlefield to your hand, as it's a land due to Toph, the First Metalbender.
7. Resolve the Yahenni ability
8. Repeat.

This ingenious loop turns your bounce lands and a few unlikely allies into an infinite engine, powered entirely by Toph, the First Metalbender transforming your free nontoken artifacts into lands. When you sacrifice Rakdos Carnarium to Yahenni, Undying Partisan's sacrifice ability, its death triggers the earthbend safety net of Toph, Hardheaded Teacher to return the land straight to the battlefield tapped. That new entry triggers Rakdos Carnarium's own ability, forcing you to bounce your free artifact back to your hand—which then sets off Toph, Hardheaded Teacher's cast trigger all over again when you replay it, earthbending your bounce land right back into position for another round of sacrifices.