What's here: a Reddit thread title referencing a weird server interaction at an unnamed North Beach restaurant, community comments that appear to be from an unrelated thread about a buried coin stash, and reactions describing someone sitting down uninvited and asking to eat a fry.
What's missing: the name of the restaurant, the operator or chef, the address, any confirmed details about the incident, or any on-record source. The Reddit comments about rusted coins and a buried box appear to be from a different thread entirely and have no connection to the dining anecdote.
This isn't a story that can be responsibly reported from these materials. If the restaurant can be identified and the operator or a named party is willing to speak on record, there may be something worth covering — an unusual front-of-house moment, a staffing situation, a place with a story behind it. Until then, this is a rumor on a forum, not a piece.