The myth – The creature had green/grey skin, a too small mouth to eat with, a pot belly and an insatiable hunger. It was born of the sins of greed.
The story – She worked as a bartender, so she was well familiar with gluttony and very used to men who pawed her as she tried to do her job. But this guy was beyond all that. It was like everything he saw, he wanted. And if he wanted it, he thought it should be his. So things started disappearing whenever he was around. People were starting to catch on to him though. He was the only common denominator. They were getting angry.
To save their souls, she left the bar and went upstairs to her home altar. She gathered the ingredients for a basic summoning spell and performed the incantation. Next, she performed a transmutation spell. Then she went back to the bar and put the small bag into his pocket.
He turned a little green and decided to leave for the night. And he went home.
During the night, he passed away. As his spirit transformed, he turned into the pot belly creature of the myth. Now he would live for eternity with the hunger he had begun as a human. But as this creature he could only harm the guilty. She had saved the angry people in her bar by condemning him.