Black holes form when enough mass gets packed so close together that its gravity gets so strong that even light cannot escape it. Mass and energy are equivalent, so theoretically it is possible to create a black hole by bringing enough energy in a different form than mass together, for instance in the form of photons. This is called a kugelblitz.
Now, is it possible to create a kugelblitz by giving a small amount of mass enough kinetic energy? As far as I know, that should work, but I'm not a trained physicist. But that leads me to my second question: a particle's speed depends on the frame of reference that is used to describe it. A particle that is at rest in one frame of reference is traveling at relativistic speed in a different frame of reference. So, why does not all mass collapse into black holes? Or is there one frame of reference that is 'special' in this regard?