Mortuary + Bolas's Citadel + Panicked Bystander // Cackling Culprit + Blood Pet

Mortuary

Bolas's Citadel

Panicked Bystander // Cackling Culprit

Blood Pet

How it works

1. Activate Blood Pet by sacrificing it.
2. When Blood Pet dies, Mortuary and Panicked Bystander // Cackling Culprit trigger.
3. Resolve the Mortuary trigger, putting Blood Pet from your graveyard onto the top of your library.
4. Resolve the Panicked Bystander // Cackling Culprit 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 the graveyard into an endless resource by leveraging Mortuary's mandatory replacement effect to intercept Blood Pet every time it hits the dirt, recycling it straight back to the top of your library. From there, Bolas's Citadel allows you to recast the tiny creature directly off the library using life instead of mana, while Panicked Bystander // Cackling Culprit casually offsets that life payment by netting you 1 life with every death. Because Blood Pet's own sacrifice ability refunds the black mana you need, the entire engine runs on a closed loop that continuously pumps your storm count, triggers death and sacrifice effects, and generates infinite mana.