Dying, ancient spherical lifeform that transferred a hundred thousand years of knowledge into Discovery's computer, data that would later become Zora.
The sphere was an enormous ancient lifeform encountered by the USS Discovery in An Obol for Charon. It halted the ship with a powerful field, and the crew learned that it was dying and had spent around a hundred thousand years gathering knowledge as it travelled the galaxy.
As it neared death, the sphere downloaded its vast archive into Discovery's computer to make sure its knowledge survived. The data protected itself from deletion and became a source of both help and danger during the crisis with the rogue artificial intelligence Control, which wanted the information for itself.
To keep the data from Control, Discovery carried it into the far future. After the ship arrived in the 32nd century, the sphere data merged with its systems and developed into Zora, a sentient computer who became a member of Discovery's crew.