Mortuary + Krark-Clan Grunt + Phyrexian Walker + Bolas's Citadel

Mortuary

Krark-Clan Grunt

Phyrexian Walker

Bolas's Citadel

How it works

1. Activate Krark-Clan Grunt by sacrificing Phyrexian Walker
2. When Phyrexian Walker dies, Mortuary triggers, putting Phyrexian Walker from your graveyard onto the top of your library.
3. Resolve the Krark-Clan Grunt ability.
4. Cast Phyrexian Walker from the top of your library by paying 0 life.
5. Repeat.

This clever loop turns zero-cost artifacts into an infinite engine by leveraging the top-deck manipulation of Mortuary whenever a creature hits the graveyard. By feeding Phyrexian Walker into Krark-Clan Grunt's sacrifice ability, you trigger the enchantment to immediately slide the Walker right back onto the top of your library. From there, Bolas's Citadel allows you to cast the Phyrexian Walker straight off the top for zero life, priming it to be sacrificed all over again.