Grenzo, Dungeon Warden + Workhorse + Transplant Theorist

Grenzo, Dungeon Warden

Workhorse

Transplant Theorist

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 Transplant Theorist 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.