Nibiru. The ancient Sumerian texts depicted a large planet (Nibiru, today we call it Planet X) that entered the solar system very specifically in one of their drawings, and told how it would leave fairly quickly after it had come. In passing, it can have drastic effects on the Earth and other planets in the solar system. Annunaki. These ancient Sumerian texts also depict a race called the Annunaki (Anunaki), a race of beings that live on Nibiru, Planet X.