There is a theory in quantum cosmology which hypothesizes that our universe is a "false vacuum", meaning that it isn't in its most stable configuration. An analogy of this would be a ball rolling around on a surface with multiple dents, rolling around to each of them, but only one of those dents, the deepest dent, could keep the ball in place most effectively. The theory states that our current universe is stable, however, if given the chance, it will "slide" into the true vacuum, wherein the entire universe will be engulfed and obliterated by a bubble of lower energy. The universe will then reconstruct, likely inventing new laws of physics. Since the speed of expanding is the speed of light, we would be entirely unaware of this event upon its occurrence, and we have no means of foreseeing it.
Now, a thing about this that I think is pretty neat, is if we compare this phenomenon to ancient Egyptian cosmology, it lines up with their recorded beliefs which state that the universe was formed from a sea of nothingness and repulsion between ether and matter, and that it will one day return to that state.