Toph, the First Metalbender + Toph, Hardheaded Teacher + Thaumatog + Rakdos Carnarium

Toph, the First Metalbender

Toph, Hardheaded Teacher

Thaumatog

Rakdos Carnarium

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 Thaumatog 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 Thaumatog ability
8. Repeat.

This clever loop transforms free artifacts into an endless cascade of triggers by turning them into lands via Toph, the First Metalbender. Once that foundation is set, casting your zero-mana artifact lets Toph, Hardheaded Teacher earthbend Rakdos Carnarium into an animated land, which you can immediately feed to Thaumatog's sacrifice ability. Because Rakdos Carnarium is a land, its death triggers Toph, Hardheaded Teacher to return it straight to the battlefield tapped, where its own entry trigger forces you to bounce the original artifact back to your hand to be recast.