Wikipedia
Juok is the name of god for the tribes on the upper reaches of the Nile. For some including the Shilluk, Dinka and Nuer, he is the Creator God and is omnipresent. Nyikang, a legendary king, is often invoked as an intermediary. Other Nilotic tribes, for example the Acholi and Lango, use the possibly related term Jok only for local and/or ancestral spirits.Cotterell, Arthur (1979)
The creator Juok moulded all people of earth. While he was engaged in the work of creation, he wandered about the world.
In the land of the whites he found a pure white earth or sand, and out of it he shaped white people. Then he came to the land of Egypt and out of the mud of the Nile he made red or brown people. Lastly, he came to the land of the Shilluks, and finding there black earth he created black people out of it. The way in which he modeled human beings was this. He took a lump of earth and said to himself, "I will make humans, but they must be able to walk and run and go out into the fields, so I will give each of them two long legs, like the flamingo." Having done so, he thought again, "They must be able to cultivate millet, so I will give each of them two arms, one to hold the hoe, and the other to tear up the weeds." So he gave humans two arms. Then he thought again, "They must be able to see the millet, so I will give them two eyes." He did so accordingly. Next he thought to himself, "They must be able to eat their millet, so I will give each a mouth." And a mouth he gave accordingly. After that he thought within himself, "They must be able to dance and speak and sing and shout, and for these purposes they must have tongues." And tongues he gave accordingly. Lastly the Deity said to himself, "They must be able to hear the noise of the dance and the speech of the great ones, and for that they need two ears." So two ears each he gave, and sent them out into the world as perfect humans."
Another story about Juok, is that he gave birth to several children—an elephant, a buffalo, a lion, a crocodile, a dog, and finally the first humans, a boy and a girl.
Juok was not pleased with the humans, so he told the dog to get rid of them. Instead, the dog nurtured the children until they were grown. By then the land had become crowded, so Juok decided to set apart land for his different creatures and give them weapons. He planned to deal with the humans last of all. The dog knew that if this happened, there would be no land or weapons left for the humans; the animals would get it all. He told the man to tell Juok that he was the elephant, buffalo, and lion. When the man did, Juok gave him all the spears. When the animals arrived, there were no spears left for them. Instead, Juok gave the elephant tusks, the buffalo horns, the lion strong claws, and the crocodile sharp teeth. The man used his spears to drive off the animals; then he took the best land for himself. A myth about the origin of death describes how a dog helped people attain long lives. In the beginning, death was not permanent. People remained dead for three days and then came back to life. One day, Juok decided to make death permanent by throwing a rock into the river. The dog urged humans to get together and haul the rock out of the river, but they ignored him. The dog was unable to get the rock out by himself, but he managed to break off a large chunk of it and carry it home. Because of this, humans have longer lives than they might have had. A Dictionary of World Mythology.