Mortuary + Wild Cantor + Bolas's Citadel + Overgrowth Elemental

Mortuary

Wild Cantor

Bolas's Citadel

Overgrowth Elemental

How it works

1. Activate Wild Cantor by sacrificing it.
2. When Wild Cantor dies, Mortuary and Overgrowth Elemental trigger.
3. Resolve the Mortuary trigger, putting Wild Cantor from your graveyard onto the top of your library.
4. Resolve the Overgrowth Elemental trigger, causing you to gain 1 life
5. Cast Wild Cantor from the top of your library by paying 1 life.
6. Repeat.

This clever loop turns life into a self-sustaining engine by letting you cast the same creature over and over again from the top of your library. Bolas's Citadel provides the crucial ability to bypass mana costs entirely, letting you cast Wild Cantor straight off the library by paying its life cost instead. Each time you sacrifice the Cantor for mana, Mortuary catches it on its way to the graveyard and neatly stacks it right back on top of your library for the Citadel to play again. Meanwhile, Overgrowth Elemental watches the chaos unfold, padding your life total with every death to completely offset the life you spend casting your spells.