On August 15th, why are there grandpa rabbit and grandma rabbit?

The rabbit is the jade rabbit in the moon palace. It is made into a clay doll, an old folk thing in Beijing and a mascot. Lucky doll for Mid-Autumn Festival in old Beijing: One year, a plague broke out suddenly in Beijing, and almost every family had patients and no medicine to eat. Chang 'e in the Moon Palace was very sad to see the scene of burning incense and seeking medical treatment, so she sent jade rabbits around her to the world to eliminate disasters and treat diseases. Jade rabbit turned into a girl and came to Beijing. She visited from house to house and cured many patients. People want to give Yutu something to thank her. But Yutu wants nothing but to borrow clothes from others. In this way, Yutu changed her costume everywhere, sometimes dressed as an oil seller, and sometimes dressed as a fortune teller ... for a while, she dressed as a man, and for a while she dressed as a woman. In order to treat more patients, Jade Rabbit rode horses, deer, or women rode lions and tigers all over Beijing. The Jade Rabbit eradicated the plague in Beijing and returned to the Moon Palace. However, her beautiful image remains in the hearts of Beijingers forever. As a result, people created the image of Jade Rabbit with clay sculpture, including those riding deer, riding phoenix, wearing armor and various work clothes. They are cute in every way. Every day on the fifteenth day of the eighth lunar month, every family will worship her and give her delicious fruits and beans as a reward for her good luck and happiness. People also affectionately call her "Grandpa Rabbit" and "Grandma Rabbit".