Red Moon Spring

Red Moon Spring is a type of Secret Room found in Lenile Cavern. It is found on floors 10-20 at all times, though you can only revive a fossil during Night.

It serves a special purpose and has a different layout than the common Secret Room.

Differences
Instead of the common Deluxe Boxes that are found in other Secret Rooms, this one offers no boxes. Instead, it can spawn fossil Pokémon if the player has the necessary items.

Pokemon
The Pokémon that can be found here are all the fossil Pokémon, depending on which Pokémon fossil they bring with them. Fossils can be found in a variety of dungeons, but mainly Tanren Chambers. There are also fossils inside Mt. Skylift and Crystal Ruins. This is a list of the fossils as well as what they spawn inside the Red Moon Spring:
 * Old Amber - Aerodactyl
 * Claw Fossil - Anorith
 * Root Fossil - Lileep
 * Cover Fossil - Tirtouga
 * Plume Fossil - Archen
 * Dome Fossil - Kabuto
 * Armor Fossil - Shieldon
 * Skull Fossil - Cranidos
 * Helix Fossil - Omanyte
 * Jaw Fossil - Tyrunt
 * Sail Fossil - Amaura

Fossil Locations
Fossils can be found in many different dungeons inside Secret Rooms. The fossils are found in these areas:
 * Old Amber - Mt. Skylift and Tanren Chambers/Flying
 * Claw Fossil - Tanren Chambers/Bug
 * Root Fossil - Tanren Chambers/Grass
 * Plume Fossil - Tanren Chambers/Fighting
 * Dome Fossil - Crystal Ruins
 * Armor Fossil - Tanren Chambers/Steel
 * Skull Fossil - Tanren Chambers/Rock
 * Helix Fossil - Tanren Chambers/Water
 * Jaw Fossil - Dragon's Descent Depths and Tanren Chambers/Dragon

The fossils that are found in Tanren Chambers are all found in different chambers, and they are on the high floors (see Tanren Chambers for more information). The other fossils can be found in Mt. Skylift, Crystal Ruins, and Sentimental Aquifer. They are invisible on the ground of the dungeons, usually on the higher floors (see respective dungeons for more information).

Recruitment
When you summon the Pokémon via fossil, the Pokémon will be the living counter-part of the item as a level 25 base form, with a recruitment of +1000 (always recruitable).

Trivia

 * The time for Red Moon Spring changed a lot during the game