Toph, the First Metalbender + Haru, Hidden Talent + Firdoch Core + Umbral Collar Zealot

Toph, the First Metalbender

Haru, Hidden Talent

Firdoch Core

Umbral Collar Zealot

How it works

1. Cast Firdoch Core by paying 3.
2. When Firdoch Core enters, Haru triggers, earthbending Firdoch Core, as it's a land due to Toph.
3. Activate Umbral Collar Zealot by sacrificing Firdoch Core.
4. When Firdoch Core dies, Haru triggers, returning Firdoch Core from your graveyard to the battlefield.
5. When Firdoch Core enters, Haru triggers, earthbending Firdoch Core, as it's a land due to Toph.
6. Resolve the Umbral Collar Zealot ability.
7. Repeat from step 3.

This clever loop transforms a humble artifact into an immortal engine by turning it into a land and abusing its dual identity. Because Toph, the First Metalbender makes all your nontoken artifacts into lands, Firdoch Core enters the battlefield both as an artifact and a land, while its changeling ability ensures it also counts as an Ally to trigger Haru, Hidden Talent. You can then sacrifice Firdoch Core to Umbral Collar Zealot's ability, sending it to the graveyard where its earthbend-granted return clause kicks in to bring it right back to the battlefield.