Black hole do it yourself

When moving at near-light speed, a moving object begins to decrease and “grow heavy” for the observer from the side. The effect of large mass is large gravity.

In order not to dangle around the universe, you just need to rotate in two axes.
You can calculate what should be the radial velocity, so that the linear was close to the light.

Total: we take some “ball”, we start to unwind it, at a certain speed we get a “black hole”: a small one and a mega-heavy one.