Requires

Whitemane Lion must be in hand. Mana Echoes must be on the battlefield. Chromatic Orrery must be on the battlefield. You control at least one Cat. Mana needed:

Steps

1. Cast Whitemane Lion by paying .
2. When Whitemane Lion enters the battlefield, it and Mana Echoes trigger.
3. Resolve the Mana Echoes trigger, adding for each Cat you control.
4. Resolve the Whitemane Lion trigger, returning it to your hand from the battlefield.
5. Repeat.
6. If you control at least two Cats outside of Whitemane Lion, this combo nets infinite mana.

Results