Mortuary + Bolas's Citadel + Bastion of Remembrance + Myr Scrapling

Mortuary

Bolas's Citadel

Bastion of Remembrance

Myr Scrapling

How it works

1. Activate Myr Scrapling by sacrificing it.
2. When Myr Scrapling dies, Mortuary and Bastion of Remembrance trigger.
3. Resolve the Mortuary trigger, putting Myr Scrapling from your graveyard onto the top of your library.
4. Resolve the Bastion of Remembrance trigger, causing you to gain 1 life and each opponent to lose 1 life.
5. Resolve the Myr Scrapling ability.
6. Cast Myr Scrapling from the top of your library by paying 1 life.
7. Repeat.

This elegant loop turns the humble Myr Scrapling into an endless engine of life and death, entirely fueled by paying life instead of mana. With Bolas's Citadel granting you the ability to cast spells directly from the top of your library, you can replay the sacrificed automaton immediately after Mortuary tucks it right back where it started. Meanwhile, Bastion of Remembrance capitalizes on every single iteration by draining your opponents and padding your life total, ensuring you have plenty of life to spare to keep casting the Scrapling over and over again.