Toph, the First Metalbender + Toph, Hardheaded Teacher + Ashnod's Altar + Boros Garrison

Toph, the First Metalbender

Toph, Hardheaded Teacher

Ashnod's Altar

Boros Garrison

How it works

1. Cast the artifact by paying 0.
2. Toph, Hardheaded Teacher triggers, earthbending Boros Garrison.
3. Resolve the artifact spell.
4. Activate Ashnod's Altar by sacrificing Boros Garrison.
5. When Boros Garrison dies, Toph, Hardheaded Teach triggers, returning Boros Garrison from your graveyard to the battlefield tapped.
6. When Boros Garrison 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. Repeat.

This clever loop turns the battlefield into an engine by transforming your zero-cost artifacts into lands using Toph, the First Metalbender. Once that foundation is set, Toph, Hardheaded Teacher triggers upon casting your artifact, earthbending Boros Garrison so it's ready to be sacrificed to Ashnod's Altar for a pair of colorless mana. Because Boros Garrison is temporarily a land via Toph's aura, its own entry trigger bounces the artifact back to your hand when it returns from the graveyard, fueled by Toph, Hardheaded Teacher's safety net.