Mortuary + Sarcatog + Phyrexian Walker + Gwenom, Remorseless

Mortuary

Sarcatog

Phyrexian Walker

Gwenom, Remorseless

How it works

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

This loop relies on Phyrexian Walker's zero mana cost to feed Sarcatog's sacrifice outlet, generating an endless cascade of creature deaths and sacrifices. Whenever the artifact creature hits the graveyard, Mortuary quietly ensures it goes straight back to the top of your library instead of staying put. Gwenom, Remorseless then leverages its attacking ability to let you cast that exact same Phyrexian Walker directly off the top of your library, trading its mana value for life—which costs you a cool zero.