This crystal maintains the existence of Terra Vapos, is a very rare and valuable Crystal and can be found on dragon's body, an very rare creature and almost in extinction.
It is extremely rare and almost extinct, and can only be found from the stomach of a dragon. Stork mentions no one has seen Serpergris for thousands of years. There is an ancient den that held the last known deposit of Serpergris, where Finn and Stork retrieve it to save Terra Vapos from their plague.
Serpergris was possibly based on magic stone called Draconia, legends say that this stone is the energy point of dragons and can be found in is head, chest or tail, curiously in some dubs, the voice actors called this stone Draconia, or similar names as Dracofell (in Portugal dubbing for example).