If we know the mass of a black hole and how fast it spins, then from Einstein’s relativistic laws we can deduce all the hole’s other properties: its … - Kip S. Thorne

Matthew Choptuik, a postdoctoral student at the University of Texas, carried out a simulation on a supercomputer that he hoped would reveal new, unexpected features of the laws of physics; and he hit the jackpot. What he simulated was the implosion of a gravitational wave.47 When the imploding wave was weak, it imploded and then disbursed. When it was strong, the wave imploded and formed a black hole. When its strength was very precisely “tuned” to an intermediate strength, the wave created a sort of boiling in the shapes of space and time. The boiling produced outgoing gravitational waves with shorter and shorter wavelengths. It also left behind, at the end, an infinitesimally tiny naked singularity

There is a maximum spin rate that any black hole can have. If it spins faster than that maximum, its horizon disappears, leaving the singularity inside it wide open for all the universe to see; that is, making it naked — which is probably forbidden by the laws of physics

Journey into Gravity and Spacetime (Wheeler, 1990).