Yeah. I can't do the physics myself, so I take on faith (heh) that a sufficiently fast rotating blackhole has a ring shaped singularity that can extend outside

Yeah. I can't do the physics myself, so I take on faith (heh) that a sufficiently fast rotating blackhole has a ring shaped singularity that can extend outside its' event horizon. This was news in the 90s and it was a plot point in at least two scifi books, though I don't think I can recommend either