Showdown of the Skalds + Crystalline Crawler + Shrieking Drake + Primal Vigor

Showdown of the Skalds

Crystalline Crawler

Shrieking Drake

Primal Vigor

How it works

1. Cast Shrieking Drake, putting 2 +1/+1 counter on Crystalline Crawler with Showdown of the Skalds.
2. Remove a +1/+1 counter from Crystalline Crawler to add .
3. Shrieking Drake triggers, returning itself to your hand.
4. Repeat.

This clever loop relies on Shrieking Drake's mandatory self-bounce trigger to continually reset its own entry, letting you repeatedly recast it using the mana generated by Crystalline Crawler. Whenever you cast the Drake, Showdown of the Skalds triggers to distribute +1/+1 counters to Crystalline Crawler, which Primal Vigor then doubles to net you a surplus of counters. You can then strip those counters away for any color of mana to pay for the Drake's recast, looping the process to generate infinite resources and an infinitely massive creature.