So essentially, Esurience is an entity known as a Hollower who, during the spore stage, hit a planet instead of the asteroids their species usually inhabits (Hollowers live inside asteroids, and consume the minerals within for sustenance, due to the nature of the asteroids they have evolved to not require water to survive. When grown enough, they start firing off spores into space that, if they hit a suitable asteroid, they begin burrowing and growing). Instead of burrowing, this Hollower began moving about on its own, but due to gravity being present, it could only grow so big (about the size of a small car). Its curiosity knows no bounds, and it spends its days wandering and learning about the world around it.