Grenzo, Dungeon Warden + Workhorse + Tomb Trawler

Grenzo, Dungeon Warden

Workhorse

Tomb Trawler

How it works

1. Activate Workhorse by removing a +1/+1 counter from it, adding C.
2. Repeat step 1 until Workhorse dies as a state-based action due to having 0 toughness.
3. Activate Tomb Trawler by paying 2, putting Workhorse from your graveyard onto the bottom of your library.
4. Activate Grenzo by paying 2, putting Workhorse from the bottom of your library into your graveyard, and then putting it onto the battlefield with four +1/+1 counters on it due to its static effect.
5. Repeat.

This cunning loop transforms Workhorse into an endlessly recycling engine, starting as you strip away its own counters to generate the colorless mana needed to keep the machinery turning. Once Workhorse finally perishes from depleted toughness, Tomb Trawler steps in to quietly slip it right back to the bottom of your library. From there, Grenzo, Dungeon Warden uses its activated ability to reach deep and pull Workhorse straight back onto the battlefield, where it conveniently resets with a fresh batch of four +1/+1 counters to begin the cycle anew.