Falling into a black hole, such as the one at the center of the galaxy Ton 618, is an extraordinary and extreme scenario. The nature of what would happen to an object or a person falling into a black hole is described by the theory of general relativity, but our understanding is limited as we have not yet reconciled general relativity with quantum mechanics. That being said, based on our current understanding, here's what we know:
As an object approaches the event horizon of a black hole, which is the boundary beyond which nothing can escape its gravitational pull, it experiences a phenomenon known as gravitational time dilation. This means that time appears to slow down from the perspective of an outside observer. From the point of view of the falling object, however, it would continue to experience time passing normally.
Once the object crosses the event horizon, it enters the region of space inside the black hole called the singularity. At the singularity, the gravitational forces become infinitely strong and the curvature of spacetime becomes extremely severe. This is where our understanding breaks down, as the laws of physics as we currently know them cannot fully describe the conditions within the singularity.
According to general relativity, the tidal forces near the singularity of a black hole would be extremely strong, causing a phenomenon known as "spaghettification." In this process, the difference in gravitational pull on different parts of the falling object becomes so great that it gets stretched and elongated. For an object like a human, this would lead to a rather unpleasant fate of being torn apart.
However, it's important to note that our understanding of black holes and their interiors is still an active area of research, and the effects of quantum mechanics on such extreme conditions are not yet fully understood. Quantum gravitational effects could potentially modify the behavior near the singularity, but a complete theory of quantum gravity is still an open question.
Overall, falling into a black hole is considered an irreversible and highly destructive process according to our current understanding.