Primal Prayers + Decoction Module + Kor Skyfisher

Primal Prayers

Decoction Module

Kor Skyfisher

How it works

1. Cast Kor Skyfisher by paying E due to Primal Prayers, if able, or by paying its mana cost.
2. When Kor Skyfisher enters the battlefield, it and Decoction Module trigger.
3. Resolve the Decoction Module trigger, causing you to get E.
4. Resolve the Kor Skyfisher trigger, returning it from the battlefield to your hand.
5. Repeat.