found this interesting:
Big Bang A 'Mirage' Caused By A 4D Black Hole. Maybe
Basically the theory is our 3D universe was created from a 4D star implosion which created a 4D black hole with a 3D event horizon, in which our 3D universe exists.
Much like our 3D stars implode and create 3D blackholes with 2D event horizons.
Meaning in every 3D blackhole that exists here, there must be a 2D universe that exists within the event horizon.