Mortuary + Grinding Station + Shield Sphere + Gwenom, Remorseless

Mortuary

Grinding Station

Shield Sphere

Gwenom, Remorseless

How it works

1. Activate Grinding Station by tapping it and sacrificing Shield Sphere
2. When Shield Sphere dies, Mortuary triggers, putting Shield Sphere from your graveyard onto the top of your library.
3. Resolve the Grinding Station ability.
4. Cast Shield Sphere from the top of your library by paying 0 life.
5. When Shield Sphere enters, Grinding Station triggers, untapping Grinding Station.
6. Repeat.

This clever loop harnesses the zero-mana artifact Shield Sphere as an endlessly recycled sacrifice fuel for Grinding Station, which in turn untaps itself whenever that very same artifact re-enters the battlefield. To keep the engine running smoothly from the top of your library, Mortuary quietly catches Shield Sphere every time it dies, placing it right back where you need it. Meanwhile, Gwenom, Remorseless provides the alternate casting permission and life-payment lifeline that lets you cast that free zero-drop artifact repeatedly without spending a single drop of mana.