I heard this story from my mother. And later I read this legend in the local history. And it recorded the Dragon Mother's family, the date when she was born, and accidentally swallowed the egg, to every details.
During the Later Jin dynasty (937 - 951 A.D.), in County Yueqing, Zhejiang Province, China, there was a Changshan (Long-hill) Village, which is in now within the jurisdiction of Hongqiao (Rainbow Bridge) town. In the village, there lived a Ye family. In the year 937, a little girl was born, her name was Gongyu. When she was still a baby, she was betrothed to a Zhou family in the nearby county Yongjia, according to the local custom.
Every morning she went to a well to fetch a pail of water. This well connects to the Eastern China Sea, and the Dragon King of East China Sea had three sons, the third prince saw Gongyu, and fell in love with her. One day she was thirteen years old, she went with her sister-in-law to the well to fetch water as usual.
The dragon prince also went to the well every morning, just wanted to catch a glimpse of the beautiful girl. That morning he was late, and when he emerged out of the water, he saw Gongyu coming towards the well, the Dragon prince had no time to hide himself, so he turned himself into a five-colored eggs, which was floating in the well. Gongyu picked up the colorful stone egg, but it was so slippery, seemed to fall out of her hand, she couldn't think of anywhere except her mouth, so she put the egg into her mouth. Then suddenly she swallowed the egg.
She came home with the pail of water, and told her father about the strange egg. While she was speaking, she felt very uncomfortable, a very strange desire to get on a higher place. So she said, “Father, I felt like to get on somewhere higher.”
Her father replied, “You may stand on the Chair.”
She felt better on the chair, but after couple minutes, she wanted to get on even higher place, so her father said, “You may stand on the table.”
She seemed to feel better on the table, but not long she even had stronger desire to get on a higher place. Her father said, “You may try the roof top?”
She climbed up onto the roof, but she was so desperate, and you couldn't stay on the roof all day like a rooster, this would be very strange, and so it was. All the neighbours came to ask why Gongyu stayed on the roof top.
Gongyu asked her father where was the highest mountain. Her father said, “Cangshan Mountain is the highest.”
Gongyu said, “I am going to that mountain top. You can only come to see me in forty-nine days. ”
She prepared herself enough victuals, and set out to Cangshan. The mountain is very steep, she had to get hold the grasses to support herself up, and the grasses on the way up the mountain are still curly till today.
Gongyu's father was very concerned about her, and couldn't wait to see her daughter. After only forty-eight days, ignoring her daughter's warning, he took an umbrella with him, and set out to Cangshan mountai to look for her.
He found her daughter lying in a cave, and nine dragons, which was mistaken for snakes by her father, playing on her body. Gongyu gave birth to nine dragons, she felt strange because of being pregnant. Gongyu's father was so frightened that he hit those “snakes” with the umbrella, and broke one dragon's tail. Eight dragons flied far away into the sky and disappeared , and only the ninth Wulong (Black) dragon which was the youngest couldn't fly far with a broken tail, he dived into the nearby lake of Nanxijiang River.
Gongyu died. She turned into a white flash, and disappeared into the sky. Now many places has the name of Wulong, which was after the black broken-tailed dragon. In that county, now produces a famous Wulong green tea.
On the top of Cangshan (blue mountain) and other places, we can find the temples dedicated the Dragon Mother Zhou. Countrymen used to go there, or sacrifice the Wulong dragon with a dragon parade, to pray for rain during the dry season. Their prayers have always been responded with immediate heavy rain.