Primal Prayers + Decoction Module + Whitemane Lion

Primal Prayers

Decoction Module

Whitemane Lion

How it works

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