Rakdos, the Muscle + Priest of Gix + Haunted Crossroads + Umori, the Collector + Phantom Train

Rakdos, the Muscle

Priest of Gix

Haunted Crossroads

Umori, the Collector

Phantom Train

How it works

1. Activate Phantom Train by sacrificing Priest of Gix.
2. When Priest of Gix dies, Rakdos triggers.
3. Holding priority, activate Haunted Crossroads by paying , putting Priest of Gix from your graveyard onto the top of your library.
4. Resolve the Rakdos trigger, causing you to exile the top three cards of your library with the ability to play them until your next end step.
5. Resolve the Phantom Train ability from step 1.
6. Cast Priest of Gix from exile by paying 2
7. When Priest of Gix enters the battlefield, it triggers, adding .
8. Repeat.

This ingenious loop is anchored by Rakdos, the Muscle, which turns every sacrifice into fuel by exiling cards from an opponent's library for you to play. You feed Priest of Gix to Phantom Train—which also conveniently pumps itself with +1/+1 counters—and before the sacrifice even resolves, Haunted Crossroads lets you pay a single black mana to put Priest of Gix right back on top of your library so Rakdos exiles it. When you cast Priest of Gix back out of exile, its entry trigger generates three black mana to cleanly pay for the entire cycle while Umori, the Collector sits quietly in the background, subtly reducing your casting costs to keep the mana flowing.