Corpse of the great Rock Worm
Thought to be a cave, one wanderer ventured in. Sensing it was a trap he raced out but not before the cave entrance turned into teeth. It was soon revealed that he was in The Great Rock Worm that was only thought to be a fairy tale. Stuff of legends. Our brave adventurer fought through the innards of the great beast and made a deal with an unknown entity. Upon being freed, it was revealed the entity was a massive green Demon of unknown origin and intent. All that is known is this thing was imprisoned in the Great Worm and it was powerful enough to be forced to be the great beasts life source while having no control over The Worm. Before anymore could be learned, the Demon bursted through the roof of the Serpents' ribcage.