Mortuary + Ashes of the Abhorrent + Bolas's Citadel + Blood Pet

Mortuary

Ashes of the Abhorrent

Bolas's Citadel

Blood Pet

How it works

1. Activate Blood Pet by sacrificing it.
2. When Blood Pet dies, Mortuary and Ashes of the Abhorrent trigger.
3. Resolve the Mortuary trigger, putting Blood Pet from your graveyard onto the top of your library.
4. Resolve the Ashes of the Abhorrent trigger, causing you to gain 1 life
5. Cast Blood Pet from the top of your library by paying 1 life.
6. Repeat.

This clever loop turns a humble sacrifice outlet into an infinite engine by leveraging the top-deck manipulation of Mortuary, which instantly recycles Blood Pet back to the library whenever it hits the graveyard. Bolas's Citadel makes this loop self-sustaining by allowing you to recast Blood Pet directly from the top of your library for life instead of mana, completely bypassing traditional costs. Meanwhile, Ashes of the Abhorrent serves a dual purpose: its static ability prevents graveyard interaction from interfering, while its triggered ability offsets the Citadel's life payment by granting you 1 life every time a creature dies.