Infernal Vessel + Valkyrie's Call + Altar of Dementia

Infernal Vessel

Valkyrie's Call

Altar of Dementia

How it works

1. Activate Altar of Dementia by sacrificing Infernal Vessel.
2. When Infernal Vessel dies, it triggers, returning itself from your graveyard to the battlefield as a Demon in addition to its other types.
3. Resolve the Altar of Dementia ability.
4. Activate Altar of Dementia by sacrificing Infernal Vessel.
5. When Infernal Vessel dies, Valkyrie's Call triggers, returning Infernal Vessel from your graveyard to the battlefield as an Angel in additional to its other types.
6. Resolve the Altar of Dementia ability.
7. Repeat.

This clever loop relies on a cascading transformation to mill your entire library through endless sacrifice. By feeding Infernal Vessel to Altar of Dementia, you trigger its resurrection clause—which brings it back as a Demon and permanently alters its creature types. The very next time you sacrifice it, Valkyrie's Call intercepts the death trigger instead, returning the creature as an Angel and setting up a perpetual cycle between these two competing replacement effects. Because each iteration grows the creature's power with new counters, Altar of Dementia mills progressively larger chunks of cards until your opponent's library is completely gone.