Is there a reason, like symbolically or otherwise, that Hussie chose to have universes be contained in frogs?
In Egypt we see the Frog-headed Heket who is an Egyptian goddess of birth(ing).
As a Celtic symbol meaning, the Frog was deemed lord over all the earth, and the Celts believed it represented curative or healing powers because of its connection with water and cleansing rains.
More Western and European views focus on the Frog’s three stages of development (egg, tadpole, fully formed amphibian) to symbolize resurrectionand spiritual evolution. For these same reasons it is also a common Christian symbol for the holy trinity and resurrection. It is often seen in Christian art to express this symbolism.
In China the Frog is an emblem of Yin energy and thought of as good luck. Feng Shui practices recommend putting an image of a Frog in the east window of your home to encourage child birth and/or happy family life.
Ancient Hindus viewed the animal symbolism of frogs on a more cosmic levels, as they believe Frogs projected the world into orbit in space, and the frog was also thought to signify darkness.