This page contains spoilers for certain secret events and locations.
The Moon is an object above the first layer of The Work (Sky), composed of a unique material named "cheese". In the center of the Moon, glyphs can be found that read "CONVERGE THE EDGES", which is a hint for the player to collect the Essences and bring them to the Moon.
"Opening" the Moon
In order to "open" the Moon, the player must bring a combination of the 4 Essences and dig into its center to activate one of the 3 unique events. Each of these events will additionally reward their unique version of the "Moon Event" tree pillars.
The Void Moon
If the Essences of Air, Fire, Earth and Water are brought to the center of the Moon, the entire Moon will transform into void liquid and this message will appear:
The four essences reveal their secretThe moon's egg cracks open and it's contents have been unlocked
This is the best way to get a sizeable amount of Void Liquid.
The Drunk Moon
If the Essence of Spirits is brought along with the other Essences to the center of the Moon, the entire Moon will transform into whiskey and show this message:
The four essences reveal their secretThe moon spills and unlocks it's inebriating contents
Activating either of these versions of the event will spawn and unlock the Destruction spell.
The Gourd Moon
Throwing a Refreshing Gourd at Kolmisilmä (or simply flying on top of it with the Gourd in your inventory) will deform its body into a gourd-like shape and turn it green. Bringing the transformed Final Boss to the Moon along with the elemental Essences will transform the Moon into Healthium, and all of the Touch of spells (Touch of Blood, Touch of Gold, Touch of Oil, Touch of Smoke, Touch of Spirits and Touch of Water) will be dropped from the center of the Moon. This message will be shown: The gods are confusedWhat is that?!
The Moon is found at x = 264 and y = -25839 (y axis goes down). Parallel worlds have no Moon, though the Moon is present in New Game Plus cycles, permitting multiple Moon events to be completed within a single run.