"The frigid moon shimmers brightly."
Endothermic Energy is a post-Moon Lord crafting material dropped by most Frost Moon enemies after The Devourer of Gods has been defeated. It is occasionally used as an alternative to Nightmare Fuel, or in conjunction with Nightmare Fuel and Phantoplasm to make Ascendant Spirit Essences.
- The item is a reference to the Endothermic Fire from Don't Starve, which cools the player. The tooltip is likely a reference to the summer season in the game and when Endothermic Fire is used.