Getting "SNAed"
So at my uni there was a course messing about with IBM System Network Architecture. I wasn't in it, so I don't remember the actual course. My roommate was, though...
One of the consequences of messing about was tickling SNA bugs and getting your terminal and your login session locked. You then had to go to the operator, tell her your login, and she would force-reset it.
Well, there's another protocol called Remote Spooling Communications System (RSCS) and it was how things got printed from a remote machine, and the printers were in constant chatter.
There was a "service machine" in VM/CMS (i.e. daemon) that ran this, logged in as "RSCSN"
My roommate had the bright idea "wot if I tell the op I'm RSCSN and she forces it?"
Sure enough, she did, and suddenly all the half-dozen very large printers got very quiet. Oops.
There were beatings all around... my roommate for doing it, the operator for knowing better, and the instructor for such a misdesigned assignment.