Source : Free On-Line Dictionary of Computing

cookie monster
     
         (From the children's TV program "Sesame Street")
        Any of a family of early (1970s) hacks reported on {TOPS-10},
        {ITS}, {Multics} and elsewhere that would lock up either the
        victim's terminal (on a {time-sharing} machine) or the
        {console} (on a batch {mainframe}), repeatedly demanding "I
        WANT A COOKIE".  The required responses ranged in complexity
        from "COOKIE" through "HAVE A COOKIE" and upward.
     
        See also {wabbit}.
     
        [{Jargon File}]
     
        (1997-02-12)