Crossing the event horizon of a black hole (astrophysical bodies born from the inward collapse of a massive star) means no coming back, because a black hole is not just an invisible object, but the collection of happenings that we, who are outside of the black hole, say don’t happen at all. This extraordinary and literal hole in the fabric of spacetime deletes entire occurrences within itself from every external observer’s self-consistent history of the universe. Whoever and whatever crosses a black hole’s event horizon simply stops at the edge to an outside observer is forever stuck there to our eyes, even as that thing or person does cross the event horizon and moves inevitably towards the singularity of infinite gravitational density. It can never be a part of the spatial or temporal region that is our known universe, ever again.
What about that thing’s karma? Karma, as it is classically understood, can only be totally expunged through total liberation from samsara (the attainment of Buddhahood) or intervention through a celestial Buddha. The violent death of Maudgalyayana, one of the Buddha’s chief disciples, is commonly used as an example of the inevitability of karma. This was because he committed matricide and patricide in a previous distant life, and even with the Maudgalyayana’s attainment of arahatship, there was no escaping the severe karma for two of Buddhism’s Five Grave Offences. Like causality itself, karma is like an arrow that chases the sentient being through infinite past lives and infinite future lives, ripening with a ruthless yet not immediately discernable inevitability.