dragon

dragon n.  [MIT] A program similar to a {daemon}, except
   that it is not invoked at all, but is instead used by the system to
   perform various secondary tasks.  A typical example would be an
   accounting program, which keeps track of who is logged in,
   accumulates load-average statistics, etc.  Under ITS, many
   terminals displayed a list of people logged in, where they were,
   what they were running, etc., along with some random picture (such
   as a unicorn, Snoopy, or the Enterprise), which was generated by
   the `name dragon'.  Usage: rare outside MIT -- under UNIX and most
   other OSes this would be called a `background demon' or
   {daemon}.  The best-known UNIX example of a dragon is
   `cron(1)'.  At SAIL, they called this sort of thing a
   `phantom'.