Toph, the First Metalbender + Toph, Hardheaded Teacher + Azorius Chancery + Phantom Train

Toph, the First Metalbender

Toph, Hardheaded Teacher

Azorius Chancery

Phantom Train

How it works

1. Cast the artifact by paying 0.
2. Toph, Hardheaded Teacher triggers, earthbending Azorius Chancery.
3. Resolve the artifact spell.
4. Activate Phantom Train by sacrificing Azorius Chancery.
5. When Azorius Chancery dies, Toph, Hardheaded Teach triggers, returning Azorius Chancery from your graveyard to the battlefield tapped.
6. When Azorius Chancery 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 ingenious loop transforms ordinary artifact casting into an engine of endless iteration by turning your non-token artifacts into lands through Toph, the First Metalbender. With that foundation set, the passive earthbending triggers from Toph, Hardheaded Teacher animate Azorius Chancery into a creature so that it can be freely sacrificed to fuel Phantom Train. Because Azorius Chancery is treated as a land by the First Metalbender, its death triggers the Teacher to return it to the battlefield tapped, and its subsequent entry-the-battlefield ability bounces your free-cost artifact right back to your hand to start the cycle anew.