Propagator Drone + Earthcraft + Zirda, the Dawnwaker

Propagator Drone

Earthcraft

Zirda, the Dawnwaker

How it works

1. Activate a basic Forest by tapping it, adding .
2. Activate Propagator Drone by paying 1, creating a 0/1 Eldrazi Spawn creature token.
3. Activate Earthcraft by tapping the Eldrazi Spawn, untapping the basic Forest.
4. Activate the Eldrazi Spawn by sacrificing it, adding C.
5. Repeat.

This loop creates an endless cycle of creature births and sacrifices by heavily discounting the tools of creation. With Zirda, the Dawnwaker reducing activated ability costs, the activation fee for Propagator Drone's token-making ability drops to an affordable single green mana. You tap a basic Forest for mana, spend it to trigger Propagator Drone and create a 0/1 Eldrazi Spawn token, then use Earthcraft to tap that newly hatched Spawn to untap your basic Forest. Finally, you sacrifice the Eldrazi Spawn for colorless mana to fuel the next iteration, generating infinite entry, death, and sacrifice triggers in the process.