Toph, the First Metalbender + Toph, Hardheaded Teacher + Boros Garrison + Phantom Train

Toph, the First Metalbender

Toph, Hardheaded Teacher

Boros Garrison

Phantom Train

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 Phantom Train 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. Resolve the Phantom Train ability
8. Repeat.

This clever loop turns the static land-types granted by Toph, the First Metalbender into a relentless engine of recursion. By casting a free artifact, you trigger Toph, Hardheaded Teacher to earthbend Boros Garrison into a creature, allowing you to feed it to Phantom Train's sacrifice ability. As the bounceland hits the graveyard, Toph, Hardheaded Teacher's earthbend clause ensures it safely returns to the battlefield, where its enter-the-battlefield trigger bounces the original artifact right back to your hand because Toph, the First Metalbender has made it a land.