Why did Zhou Wenwang vomit a rabbit after eating his eldest son on the list of gods? What does this mean?

This is a story in the Romance of Gods. It is said that Xibo Hou Jichang managed to eat the meat pie baked by his son Boyi in order to escape Shang Zhouwang's imprisonment. After fleeing back to his hometown, he vomited three meatballs. Meatballs become small animals with long ears when they see the wind, and later they are called rabbits, which take the sound of "spitting".