Main sequence, supergiants, white dwarfs, neutron stars, black holes - the only major difference is mass (and fusion but that's a different story for another time). That's it. Following a white dwarf, some laws and forces of nature get violated or at the very least, close to it. With neutron stars, we have the pauli exclusion principle and electromagnetism getting violated. Since the star is so massive, gravity overpowers everything minus the speed of light. With black holes, the speed of light (being a constant) becomes violated as well as several other laws, some of which we haven't even discovered yet. Willing to bet, black holes even fuck up neutrons and the quarks within them. They would have to considering that everything is compressed into a single singularity and it breaks most of the laws we have set in place but here we are regardless.
Honestly, they aren't that mysterious anymore. We already know most things about them despite not being able to see past the event horizon. We even have a fairly good timeline of the far future and how long it will take for black holes to decay.
Sorry guys, need to find some new space mystery to circlejerk.