Leonardo, Sewer Samurai + Solemnity + Krark-Clan Grunt + Phyrexian Walker

Leonardo, Sewer Samurai

Solemnity

Krark-Clan Grunt

Phyrexian Walker

How it works

1. Activate Krark-Clan Grunt 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 loop turns a humble 0-mana artifact creature into an engine of endless power by combining graveyard recursion with absolute protection against counters. With Solemnity on the battlefield, its static ability prevents any counters from being placed on permanents, which neatly bypasses the finality counters that Leonardo, Sewer Samurai would normally impose on creatures cast from the graveyard. This allows you to repeatedly cast Phyrexian Walker for free from your graveyard turn after turn, feeding it directly into Krark-Clan Grunt to fuel infinite sacrifices, leaves-the-battlefield, and death triggers while pumping the Grunt to astronomical heights.