Mortuary + Megatog + Phyrexian Walker + Bolas's Citadel

Mortuary

Megatog

Phyrexian Walker

Bolas's Citadel

How it works

1. Activate Megatog 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 Megatog ability.
4. Cast Phyrexian Walker from the top of your library by paying 0 life.
5. Repeat.

This ingenious loop turns the humble Phyrexian Walker into a repeating sacrifice engine, feeding it endlessly to Megatog to pump its power to astronomical heights. Every time the artifact creature hits the graveyard, Mortuary neatly places it right back on top of your library, primed and ready. Meanwhile, Bolas's Citadel allows you to cast that very same top card over and over again, bypassing its mana cost entirely by paying zero life instead.