Toph, the First Metalbender + Toph, Hardheaded Teacher + Phyrexian Altar + Golgari Rot Farm

Toph, the First Metalbender

Toph, Hardheaded Teacher

Phyrexian Altar

Golgari Rot Farm

How it works

1. Cast the artifact by paying 0.
2. Toph, Hardheaded Teacher triggers, earthbending Golgari Rot Farm.
3. Resolve the artifact spell.
4. Activate Phyrexian Altar by sacrificing Golgari Rot Farm.
5. When Golgari Rot Farm dies, Toph, Hardheaded Teach triggers, returning Golgari Rot Farm from your graveyard to the battlefield tapped.
6. When Golgari Rot Farm 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 transforms a humble zero-mana artifact into a perpetual motion machine by rewriting the rules of the battlefield. With Toph, the First Metalbender turning your nontoken artifacts into lands, every artifact you cast and bounce becomes a movable land drop. Toph, Hardheaded Teacher provides the earthbending engine to turn those land-artifacts into creatures so they can be fed directly to Phyrexian Altar for mana, while simultaneously triggering a bounce loop when Golgari Rot Farm enters the battlefield to pick the artifact right back up to your hand.