The story you are referring to comes from Hindu mythology and is associated with the divine child Krishna. According to the legends, Yashoda Ma, who was Krishna's foster mother, witnessed a miraculous event where she saw the entire universe within Krishna's mouth.
The incident is described in the Bhagavata Purana, an ancient Hindu scripture. In the story, young Krishna was mischievously eating dirt, and upon discovering this, Yashoda Ma scolded him and asked him to open his mouth. To her astonishment, she saw a cosmic vision within his mouth, which included various celestial realms, universes, and divine forms.
The event holds symbolic significance rather than being a literal occurrence. It represents Krishna's divine nature and his identity as the Supreme Being or God. The vision of the universe within Krishna's mouth is a metaphorical representation of his cosmic power and his all-encompassing nature.
In Hindu philosophy, it is believed that God encompasses everything and is present within every atom of the universe. The incident of Yashoda Ma seeing the universe in Krishna's mouth serves to highlight this concept of divine omnipresence and the limitless nature of God's existence.
It is important to note that these stories are part of religious mythology and are interpreted and understood in the context of religious beliefs and practices. Different interpretations and variations of the story may exist within different sects and traditions of Hinduism.