Rakdos, the Muscle + Priest of Gix + Haunted Crossroads + Goblin Bombardment + Cloud Key

Rakdos, the Muscle

Priest of Gix

Haunted Crossroads

Goblin Bombardment

Cloud Key

How it works

1. Activate Goblin Bombardment 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 Goblin Bombardment ability from step 1, dealing 1 damage to any target.
6. Cast Priest of Gix from exile by paying 2.
7. When Priest of Gix enters the battlefield, it triggers, adding .
8. Repeat.

This cunning loop relies on using Haunted Crossroads to continually stack Priest of Gix back onto your library, where Rakdos, the Muscle can then exile it to be cast again. Since Cloud Key has discounted creatures to cost just two mana, casting the Priest requires only a portion of the black mana generated by its own entrance trigger. Meanwhile, Goblin Bombardment provides the sacrifice outlet needed to fuel the chain, dealing infinite damage while Rakdos chips away at your opponent's library with every iteration.