It had been trapped by the intense magnetic field of Questar M-17 for three hundred million years. It had the ability to create a symbiotic connection with electromagnetic systems like those of a starship, lifeform, or planet. It also had the ability to reproduce itself in order to connect with several objects at once.
The organism planned to use the Enterprise to break orbit and head for the galactic core in the hopes of taking over the galaxy. It had originally planned to use the insectoid ship for this purpose, but its crew destroyed the ship to prevent the organism's escape. Its current location is Questar M-17.
It took control of the dead star because the Enterprise flew straight towards it until the organism fled the ship for safety. The Enterprise then flew away from Questar M-17 while hearing the magnetic organism's desperate cry for help out of fear of being lonely. (TAS: "Beyond the Farthest Star")