With a surface temperature of hundreds of thousands of degrees and a gravity billions of times higher than Earth's, the Vulcan Forge was inaccessible to anyone except gods and Talos robots. It housed an industrial complex entirely made of Neutral Matter, capable of resisting the tremendous heat and pressure.
When Noriko Null hacked the Forge's technology to make the complex and the Talos robots as heavy as neutron star matter, the star quickly became highly unstable thanks to the increased mass and collapsed into a black hole. (Beyond The Impossible #206)
First appereance: Beyond The Impossible #63