Host ghost

A specific type of ghost in a chatroom or other communication service who appears yet present, while in fact already gone, as a result or side effect of a host error. Many services offer a command to erase them from the list of people present as well as other type of ghosts, such as NickServ's /ns ghost.

I have spent a few minutes to write a private message to a host ghost until I realized they have disconnected before I began.