The tiangou (Chinese: 天狗; pinyin: tiāngǒu; Wade–Giles: t'ien1-kou3; lit. 'Heavenly Dog') is a legendary creature from China. The tiangou resembles a black dog or meteor, which is thought to eat the moon during an eclipse. Tales explain that you must beat dogs and drive them away in order to ward off the tiangou. The dog god would then spit out the moon and flee back into the heavens.
Battle with Zhangxian
Zhang Xian (Chinese: 張仙; pinyin: Zhāng Xiān) is the enemy of the tiangou. It is said that he protects his children from the god with his bow and arrows. He is often depicted aiming at the sky, waiting for the beast to appear.
He is the god of birth and the protector of male children. Many sought for him to give them male offspring and to protect their living children.
Derivatives
The tengu of Japanese folklore was derived from the tiangou. The tengu is usually depicted as a bird, or man with a long nose and other bird-like characteristics, while the tiangou is a dog.