Mortuary + Krark-Clan Grunt + Memnite + Bolas's Citadel

Mortuary

Krark-Clan Grunt

Memnite

Bolas's Citadel

How it works

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

This clever engine turns the zero-cost artifact Memnite into an infinite sacrifice loop to pump Krark-Clan Grunt to astronomical heights. Because Memnite costs zero mana, you can continually replay it off the top of your library for free using the alternative life-payment ability granted by Bolas's Citadel. Whenever the tiny automaton hits the graveyard, Mortuary neatly recycles it right back to the top of your library, allowing you to feed it to Krark-Clan Grunt over and over again.