When we see this behavior in adults it is typically in someone in a mental hospital, solitary confinement or other extreme setting.
Do you have any clues, hunches, or more information? We would certainly wonder who, but also why now
A member recently posted a similar post on the mental health expert forum. In that case it was a family member. My impression from the question and answer was that the individual must be seriously disturbed (and that they should be receiving treatment).
The behavior sounds kind of anti-social.
Good luck finding this person and helping them get treatment.