Mortuary + Bile Urchin + Bolas's Citadel + Venerated Stormsinger

Mortuary

Bile Urchin

Bolas's Citadel

Venerated Stormsinger

How it works

1. Activate Bile Urchin by sacrificing it.
2. When Bile Urchin dies, Mortuary and Venerated Stormsinger trigger.
3. Resolve the Mortuary trigger, putting Bile Urchin from your graveyard onto the top of your library.
4. Resolve the Venerated Stormsinger trigger, causing you to gain 1 life and each opponent to lose 1 life.
5. Resolve the Bile Urchin ability.
6. Cast Bile Urchin from the top of your library by paying 1 life.
7. Repeat.

This elegant little loop turns a humble goblin into a self-sustaining life-drain engine. Bolas's Citadel does the heavy lifting by allowing you to cast spells directly from the top of your library for life instead of mana, while Mortuary catches Bile Urchin the moment it hits the graveyard and immediately tucks it right back onto the top of your library. As the Urchin cycles endlessly through this loop, Venerated Stormsinger capitalizes on every single death to drain your opponents dry and offset the life cost paid to Bolas's Citadel.