Leonardo, Sewer Samurai + Solemnity + Phyrexian Walker + Arcbound Ravager

Leonardo, Sewer Samurai

Solemnity

Phyrexian Walker

Arcbound Ravager

How it works

1. Activate Arcbound Ravager by sacrificing Phyrexian Walker.
2. Cast Phyrexian Walker from your graveyard by paying 0. It will not enter with a finality counter on it due to Solemnity.
3. Repeat.

This elegant loop turns Leonardo, Sewer Samurai into a tireless recursion engine for zero-mana artifacts, fueled by Solemnity's preventive grace. Normally, casting a creature from your graveyard via Leonardo would brand it with a finality counter, but Solemnity steps in to ensure no counters can ever be placed on your permanents. This allows you to repeatedly cast Phyrexian Walker from the graveyard for free, sacrificing it to Arcbound Ravager each time to build an infinitely massive artifact creature while farming endless sacrifice and death triggers.