[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 timesharing 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. Folklorist Jan Brunvand (see FOAF) has described these programs as urban legends (implying they probably never existed) but they existed, all right, in several different versions. See also wabbit. Interestingly, the term cookie monster appears to be a retcon; the original term was cookie bear.