Metalwork Colossus + The Ooze + Megatog + Bloodspore Thrinax

Metalwork Colossus

The Ooze

Megatog

Bloodspore Thrinax

How it works

1. Cast Metalwork Colossus by paying 0, which enters with at least two +1/+1 counters on it due to Bloodspore Thrinax.
2. Activate Megatog by sacrificing Metalwork Colossus.
3. When Metalwork Colossus dies, The Ooze triggers, creating a Mutagen token for each +1/+1 counter Metalwork Colossus had.
4. Resolve the Megatog ability.
5. Activate Metalwork Colossus by sacrificing two Mutagens, returning it from your graveyard to your hand.
6. Repeat.

This loop transforms a free-casting artifact giant and a voracious devourer into an endless engine of artifact creation. By using Bloodspore Thrinax to ensure Metalwork Colossus enters the battlefield with massive +1/+1 counters, Megatog has a steady stream of artifacts to sacrifice while triggering The Ooze to flood the board with Mutagen tokens whenever the Colossus dies. Those very same Mutagens then pay the sacrifice cost for Metalwork Colossus's own recursion ability, bringing it right back to your hand so you can recast it for zero mana and do it all over again.