Due to the fact that much of Slavic culture and its many stories, religion, and traditions have been passed down verbally, not much recorded history is actually present. However, some creation stories were translated and scribed by monks and serve as scholarly records of mythologies and cultural beliefs. There are a few different stories surrounding the Cosmic Egg and the creation story as told by the Slavic people of old. They usually always include two main deities, one dark and one light. These deities often always are representing the underworld and the upperworld. In some tales, life is formed from an egg, while in others it may come out of the sea or even descend from the sky. Some stories even claim mankind was formed from clay, whether the god of light comes and forms angels, while the god of darkness comes to create demons, in order to, provide divine balance to the world. Despite the differences, below is one of the most commonly seen and widely spread Slavic creation stories.
This story below was copied and pasted directly from Slavorum.org
"The oldest Slavic traditions say that in the beginning there was nothing, there is old-dark, dark sea and sky, the only existing thing created by Rod was World-egg in which rested Svarog, the divine creator.
Under the influence of life forces, the egg is cracked open and create a light that shone Svarog and created its shadow, from which it originated Crnobog. Vodan, God of the sea and the water came from the glare of Svarogos old-sea.
From the top of the eggshell dust-creating the world tree, ash tree, which is rising separated the heavens from the earth and sea. His crown was created Nav, the world of the gods.
Svarog and Crnobog or Drognjuš were the force without form, so they created their counterparts, avatars, in which they acted as the counterpart to the world.
Svarog is using gold powder from the bottom of the world, fire, that created all life and the world, and created the sun and moon. Lower half of debris from an egg created humans and all other creatures on earth.
People have eventually become masters of this world have become wise, cunning, began to cultivate the land, livestock breeding, building their cities and towns, as most other creatures, mythological, and so, gradually suppressed in the rugged and wild lands and people were less encountered."
Does this story sound similar to any other creation story you've heard? Maybe from of different culture or a different time period altogether...