This one didn't actually happen to me, but it happened to Minion #1 in the library, so hence it is a Library Ghost.
Minion #1 was covering at another facility and he was happily entering the interlibrary loan requests in the database when a patron asked for his assistance in the library. He left the office in the middle of his project to help the patron and when he returned minutes later, he noticed a very strange sight. His formerly neat piles of "done" and "not done" interlibrary loan requests were messed up and in the database was a DOC number that he did not enter.
Minion #1 was intrigued, so he checked the DOC number in our offender database and he was shocked to find that it was someone WHO HAD DIED AT THAT FACILITY FIVE YEARS AGO. Unfortunately, he must have used all his spectral energy entering his number because he didn't get to the part where he said what he wanted to request. Alas, we will never know what this patron's final ILL request was. Hopefully he got it from the afterlife library.
Until next time!