Time-Lost Cavern is a node in Azurite Mine. It can only appears in Frozen Hollow biome. The path to the node may behind a wall.
Multiple essence possessed monsters. Click the Crumbling Stone to unfreeze them and start the fight.
After clearing all the monsters, clicking Crumbling Stone (the name would changed to Glyphic Fossilised Remains) again will drop Glyphic FossilGlyphic FossilStack Size: 10Has a Corrupt Essence modifierPlace in a Resonator to influence item crafting.
Shift click to unstack. .
The essence possessed monsters themselves drop essences.