Golgari Thug + Bolas's Citadel + Carrion Feeder + Vein Ripper

Golgari Thug

Bolas's Citadel

Carrion Feeder

Vein Ripper

How it works

1. Activate Carrion Feeder by sacrificing Golgari Thug.
2. When Golgari Thug dies, it and Vein Ripper trigger.
3. Resolve the Golgari Thug trigger, putting it from your graveyard onto the top of your library.
4. Resolve the Vein Ripper trigger, causing you to gain 2 life and target opponent to lose 2 life.
5. Resolve the Carrion Feeder ability.
6. Cast Golgari Thug from the top of your library by paying 2 life.
7. Repeat.

This looping engine lets you endlessly churn through your deck by weaponizing Bolas's Citadel to cast Golgari Thug right off the top of your library for a mere 2 life instead of its mana cost. Each iteration is fueled by sacrificing the Thug to Carrion Feeder, which pumps up the Feeder while triggering Golgari Thug's own death ability to stack itself right back onto the top of your library. Meanwhile, Vein Ripper sits on the battlefield watching the carnage, turning every single sacrifice and death into a draining life-swing that steadily bleeds your opponents dry while padding your own life total to keep paying the Citadel's cost.