Mortuary + Sarcatog + Bolas's Citadel + Shield Sphere

Mortuary

Sarcatog

Bolas's Citadel

Shield Sphere

How it works

1. Activate Sarcatog by 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 Sarcatog ability.
4. Cast Shield Sphere from the top of your library by paying 0 life.
5. Repeat.

This ingenious loop turns a stack of seemingly mismatched components into an infinite storm and death engine. Bolas's Citadel forms the foundation by allowing you to cast spells directly from the top of your library for life instead of mana, making Shield Sphere completely free to recast at zero life cost. As soon as you sacrifice Shield Sphere to Sarcatog, Mortuary immediately intercepts it on its way to the graveyard, placing the artifact creature right back onto the top of your library where Bolas's Citadel can grab it again. Meanwhile, Sarcatog acts as both the designated sacrifice outlet and a growing threat, while Shield Sphere serves as the ultimate expendable fuel to keep the cycle spinning endlessly.