Metalwork Colossus + The Ooze + Bartolomé del Presidio + Master Biomancer

Metalwork Colossus

The Ooze

Bartolomé del Presidio

Master Biomancer

How it works

1. Cast Metalwork Colossus by paying 0, which enters with at least two +1/+1 counters on it due to Master Biomancer.
2. Activate Bartolomé del Presidio 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 Bartolomé del Presidio ability.
5. Activate Metalwork Colossus by sacrificing two Mutagens, returning it from your graveyard to your hand.
6. Repeat.

This brilliant loop lets you continuously cast and sacrifice Metalwork Colossus for free, leveraging its massive mana value to keep its casting cost at zero. Master Biomancer ensures that the Colossus enters the battlefield with extra +1/+1 counters already attached, which is the crucial fuel that allows The Ooze to trigger and flood your board with Mutagen tokens whenever the Colossus dies. You then feed those very same Mutagen tokens back into the graveyard retrieval ability of the Colossus, while Bartolomé del Presidio happily accepts the Colossus as a sacrifice and grows larger with every iteration.