Mortuary + Carmen, Cruel Skymarcher + Bolas's Citadel + Goblin Firestarter

Mortuary

Carmen, Cruel Skymarcher

Bolas's Citadel

Goblin Firestarter

How it works

1. Activate Goblin Firestarter by sacrificing it.
2. When Goblin Firestarter dies, Mortuary and Carmen trigger.
3. Resolve the Mortuary trigger, putting Goblin Firestarter from your graveyard onto the top of your library.
4. Resolve the Carmen trigger, causing you to gain 1 life and put a +1/+1 counter on Carmen.
5. Resolve the Goblin Firestarter ability.
6. Cast Goblin Firestarter from the top of your library by paying 1 life.
7. Repeat.

This clever loop turns the humble Goblin Firestarter into a lethal weapon by exploiting a constant cycle of sacrifice and rebirth. Bolas's Citadel allows you to bypass mana costs entirely by paying life to recast the Goblin from the top of your library, a cost easily offset by the life gained from Carmen, Cruel Skymarcher each time a permanent is sacrificed. Meanwhile, Mortuary ensures the sacrificed creature never stays in the graveyard, instantly placing it back on top of your library to keep Bolas's Citadel fueled. As you repeat the process, Carmen grows indefinitely large from the accumulated +1/+1 counters, while Goblin Firestarter deals infinite damage to close out the game.