Remembrance + Mortuary + Altar of Dementia + Shield Sphere

Remembrance

Mortuary

Altar of Dementia

Shield Sphere

How it works

1. Activate Altar of Dementia by sacrificing Shield Sphere.
2. When Shield Sphere dies, Mortuary and Remembrance trigger.
3. Resolve the Mortuary trigger, putting Shield Sphere from your graveyard on top of your library.
4. Resolve the Remembrance trigger, searching your library for Shield Sphere and putting it into your hand.
5. Resolve the Altar of Dementia ability.
6. Cast Shield Sphere by paying 0.
7. Repeat.

This crafty little loop turns a humble 0-mana artifact creature into a relentless mill engine by exploiting the interaction between the graveyard and your library. When you sacrifice Shield Sphere to Altar of Dementia, both Mortuary and Remembrance trigger simultaneously; Mortuary places the Sphere right back on top of your library, while Remembrance lets you tutor another copy straight to your hand. Because Shield Sphere costs zero mana to cast, you can immediately replay it, setting the stage to feed the Altar over and over again until every opponent's library has vanished into thin air.