Mortuary + Bile Urchin + Bolas's Citadel + Popular Egotist

Mortuary

Bile Urchin

Bolas's Citadel

Popular Egotist

How it works

1. Activate Bile Urchin by sacrificing it.
2. When Bile Urchin dies, Mortuary and Popular Egotist trigger.
3. Resolve the Mortuary trigger, putting Bile Urchin from your graveyard onto the top of your library.
4. Resolve the Popular Egotist trigger, causing you to gain 1 life and target 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 clever loop uses Mortuary to constantly intercept your dying creatures and stack them right back onto the top of your library. From there, Bolas's Citadel allows you to immediately recast the creature by paying life instead of mana, bypassing traditional resource constraints. Meanwhile, Popular Egotist turns every single sacrifice into a life-drain engine, letting you turn Bile Urchin's repeated demise into a lethal stream of damage.