I don't believe in black holes really, "black holes" could just be small singularities that need to grow to the right size before they explode and create a new Universe.
I guess the black hole would have to eat a bunch of other black holes, before it becomes a large enough singularity before it explodes and creates another Universe in the Multiverse.
My theory is the "black holes" can only hold so much matter or mass before the force of gravity can no longer hold it back. Which at the point it becomes the singularity and detonates.
Or the force of gravity doesn't matter, a new material is made in the singularity/blackhole at the center and that is what causes the detonation.
Or some aliens could shoot anti-matter at it and that would make it explode.
Probably would need an insane amount of anti-matter.
