Toph, the First Metalbender + Toph, Hardheaded Teacher + Arid Archway + Phantom Train

Toph, the First Metalbender

Toph, Hardheaded Teacher

Arid Archway

Phantom Train

How it works

1. Cast the artifact by paying 0.
2. Toph, Hardheaded Teacher triggers, earthbending Arid Archway.
3. Resolve the artifact spell.
4. Activate Phantom Train by sacrificing Arid Archway.
5. When Arid Archway dies, Toph, Hardheaded Teach triggers, returning Arid Archway from your graveyard to the battlefield tapped.
6. When Arid Archway 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 Phantom Train ability
8. Repeat.

This intricate loop transforms a humble zero-mana artifact into an engine of endless triggers by weaving together active and passive pieces on your battlefield. Toph, the First Metalbender does the crucial setup work behind the scenes, turning all your nontoken artifacts into lands so that Arid Archway's bounce ability can target them. With that foundation laid, Toph, Hardheaded Teacher triggers off your spellcasting to earthbend Arid Archway into a creature, making it vulnerable to Phantom Train's sacrifice outlet. Each time Arid Archway is fed to Phantom Train, Toph's triggered ability pulls the land right back from the graveyard, and its re-entry bouncing mechanism picks up your zero-mana artifact to repeat the cycle infinitely.