Agatha of the Vile Cauldron + Propagator Drone + Chromatic Orrery

Agatha of the Vile Cauldron

Propagator Drone

Chromatic Orrery

How it works

1. Activate Propagator Drone by paying 1, creating a 0/1 Eldrazi Spawn creature token.
2. Activate the Eldrazi Spawn by sacrificing it, adding C.
3. Repeat.

This ingenious loop relies on a brilliant cost-reduction engine: Agatha of the Vile Cauldron lowers the activation cost of Propagator Drone's ability by an amount equal to Agatha's power, dropping the {3}{G} requirement down to a manageable rate. To feed this activation, you can tap Chromatic Orrery for a burst of five colorless mana, while its passive ability ensures you can freely spend that mana regardless of any color restrictions. As you cycle through Propagator Drone's ability to constantly churn out Eldrazi Spawn tokens, sacrificing those very same tokens instantly generates the colorless mana needed to keep the loop going, alongside an endless stream of artifact-based death and sacrifice triggers.