Sandy, like most of us, doesn't remember the beginning.
All Sandy knows is a big hunger in an infinite universe.
Wherever Sandy wanders, that great hunger paves the way. Remnants of hearty meals float gently in her wake. Satisfying a fervent appetite poses a problem. Sandy has a tiny mouth. She gobbles everything that fits inside and resorts to many small bites when large meals block the path. There is no destination. Sandy knows nothing about the world. Zipping from place to place suits Sandy just fine as long as there is something to eat.
The product of this voraciousness is a tiny, but generous light. The more Sandy eats, the brighter they become, but the journey goes mostly undetected. As Sandy bounces, consumes, and plows through their world, a version of every living thing presents itself. This energetic being is unseen by all; their presence theoretical, lacking empirical proof of Sandy’s existence.
But unseen universal laws dictate that every light fades and so will Sandy's.
Someday, when Sandy’s heart is full and content, if the heart does exist, all that makes Sandy special will have been spent and Sandy will disappear.
No one will notice.