Cosmic Encounter: Cosmic Eons

https://www.fantasyflightgames.com/en/news/2016/8/10/cosmic-eons/

The galaxy continues to grow with Cosmic Eons, the sixth expansion for the beloved game Cosmic Encounter.  Cosmic Eons features a Hidden Alliances in which players decide their alliances secretly and reveal them simultaneously, adding suspense, bluffing and possibly even backstabbing to the Alliance Phase. Thirty new aliens enter the game, including several who begin the game with essence cards that enable players to help, fine, traumatize, and even give bad dreams to their opponents.

This is not a standalone product. A copy of the Cosmic Encounter Core Set is required to play.