Mortuary + Cauldron Familiar + Blasting Station + Bolas's Citadel

Mortuary

Cauldron Familiar

Blasting Station

Bolas's Citadel

How it works

1. Cast Cauldron Familiar either from your hand or from the top of your library by paying or 1 life respectively.
2. When Cauldron Familiar enters, it and Blasting Station triggers.
3. Resolve the Cauldron Familiar trigger, causing each opponent to lose 1 life and you to gain 1 life.
4. Resolve the Blasting Station trigger, untapping it.
5. Activate Blasting Station by tapping it and sacrificing Cauldron Familiar.
6. When Cauldron Familiar dies, Mortuary triggers, putting Cauldron Familiar from your graveyard onto the top of your library.
7. Resolve the Blasting Station ability.
8. Repeat.

This loop creates an endless cycle of sacrifice and rebirth by letting Blasting Station pitch Cauldron Familiar, whose death triggers Mortuary to seamlessly return it right to the top of your library. From there, Bolas's Citadel allows you to play the cat directly off the library for a mere 1 life instead of its mana cost, bypassing traditional mana constraints entirely. As Cauldron Familiar enters the battlefield anew, its life-draining ability nets you the life you just paid into Bolas's Citadel while draining your opponents, and Blasting Station's untap trigger resets the apparatus for the next sacrifice.