Mortuary + Memnite + Bolas's Citadel + Phantom Train

Mortuary

Memnite

Bolas's Citadel

Phantom Train

How it works

1. Activate Phantom Train by sacrificing Memnite
2. When Memnite dies, Mortuary triggers, putting Memnite from your graveyard onto the top of your library.
3. Resolve the Phantom Train ability.
4. Cast Memnite from the top of your library by paying 0 life.
5. Repeat.

This elegant loop relies on Bolas's Citadel to turn your library into a hand, allowing you to cast Memnite directly from the top for zero life. Phantom Train provides the necessary sacrifice outlet, letting you feed it the zero-mana automaton to grow huge while triggering its ability. As soon as Memnite hits the graveyard, Mortuary instantly catches it and places it right back onto the top of your library. Because the Citadel lets you play from the top again, you can repeat this cycle endlessly to generate infinite storm count, enter-the-battlefield triggers, and a massive Phantom Train.