Peregrin Took + Cauldron Familiar + Pitiless Plunderer + Altar of Dementia

Peregrin Took

Cauldron Familiar

Pitiless Plunderer

Altar of Dementia

How it works

1. Activate Altar of Dementia by sacrificing Cauldron Familiar.
2. When Cauldron Familiar dies, Pitiless Plunderer triggers, creating a Treasure and a Food artifact token.
3. Resolve the Altar of Dementia ability, causing target player to mill cards equal to Cauldron Familiar's power.
4. Activate Cauldron Familiar by sacrificing the Food, returning Cauldron Familiar to the battlefield from your graveyard.
5. When Cauldron Familiar enters the battlefield, it triggers, causing each opponent to lose 1 life and you to gain one life.
6. Repeat.