Metalwork Colossus + The Ooze + Thermopod + Bioengineered Future

Metalwork Colossus

The Ooze

Thermopod

Bioengineered Future

How it works

1. Cast Metalwork Colossus by paying 0, which enters with at least two +1/+1 counters on it due to Bioengineered Future.
2. Activate Thermopod 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. Activate Metalwork Colossus by sacrificing two Mutagens, returning it from your graveyard to your hand.
5. Repeat.

This loop turns Metalwork Colossus into a recursive engine by using its own cost reduction to cast it for free, thanks to the noncreature artifact discount and the mana generated from Thermopod. When the Colossus hits the battlefield, Bioengineered Future ensures it enters with a pair of +1/+1 counters, which in turn feed The Ooze's trigger the moment Thermopod sacrifices the Colossus for red mana. Those resulting Mutagen tokens serve as the exact fuel needed to activate the Colossus's graveyard-return ability, allowing you to replay it infinitely and generate boundless resources.