Golgari Thug + Dross Harvester + Bolas's Citadel + Phantom Train

Golgari Thug

Dross Harvester

Bolas's Citadel

Phantom Train

How it works

1. Activate Phantom Train by sacrificing Golgari Thug.
2. When Golgari Thug dies, it and Dross Harvester trigger.
3. Resolve the Golgari Thug trigger, putting it from your graveyard onto the top of your library.
4. Resolve the Dross Harvester trigger, causing you to gain 2 life.
5. Resolve the Phantom Train ability.
6. Cast Golgari Thug from the top of your library by paying 2 life.
7. Repeat.

This ingenious loop turns life into a perpetual engine by leveraging Bolas's Citadel to cast spells directly from the top of your library for a life payment instead of mana. Phantom Train provides a reliable outlet to repeatedly sacrifice Golgari Thug, triggering its ability to stack itself right back onto the top of your library for the next iteration. Meanwhile, Dross Harvester acts as your vital life safety net, mitigating the life cost of the Citadel with the life gained every time a creature perishes.