The Jargon File (version 4.4.7, 29 Dec 2003):

Shub-Internet
 /shuhb' in?t@r?net/, n.

    [MUD: from H. P. Lovecraft's evil fictional deity Shub-Niggurath, the Black
    Goat with a Thousand Young] The harsh personification of the Internet:
    Beast of a Thousand Processes, Eater of Characters, Avatar of Line Noise,
    and Imp of Call Waiting; the hideous multi-tendriled entity formed of all
    the manifold connections of the net. A sect of MUDders worships
    Shub-Internet, sacrificing objects and praying for good connections. To no
    avail ? its purpose is malign and evil, and it is the cause of all network
    slowdown. Often heard as in ?Freela casts a tac nuke at Shub-Internet for
    slowing her down.? (A forged response often follows along the lines of: ?
    Shub-Internet gulps down the tac nuke and burps happily.?) Also cursed by
    users of the Web, FTP and telnet when the network lags. The dread name of
    Shub-Internet is seldom spoken aloud, as it is said that repeating it three
    times will cause the being to wake, deep within its lair beneath the
    Pentagon. Compare Random Number God.

    [January 1996: It develops that one of the computer administrators in the
    basement of the Pentagon read this entry and fell over laughing. As a
    result, you too can now poke Shub-Internet by pinging
    shub-internet.ims.disa.mil. Compare kremvax. ?ESR]

    [April 1999: shub-internet.ims.disa.mil is no more, alas. But Shub-Internet
    lives, and even has a home page. ?ESR]


The Free On-line Dictionary of Computing (30 December 2018):

Shub-Internet

   /shuhb in't*r-net/ (MUD, from H. P. Lovecraft's evil fictional
   deity "Shub-Niggurath", the Black Goat with a Thousand Young)
   The harsh personification of the Internet, Beast of a
   Thousand Processes, Eater of Characters, Avatar of Line Noise,
   and Imp of Call Waiting; the hideous multi-tendriled entity
   formed of all the manifold connections of the net.  A sect of
   MUDders worships Shub-Internet, sacrificing objects and
   praying for good connections.  To no avail - its purpose is
   malign and evil, and is the cause of all network slowdown.
   Often heard as in "Freela casts a tac nuke at Shub-Internet
   for slowing her down."  (A forged response often follows along
   the lines of: "Shub-Internet gulps down the tac nuke and burps
   happily.")  Also cursed by users of FTP and telnet when
   the system slows down.  The dread name of Shub-Internet is
   seldom spoken aloud, as it is said that repeating it three
   times will cause the being to wake, deep within its lair
   beneath the Pentagon.

   [Jargon File]

   (1994-11-04)