tentacle

tentacle n.  A covert {pseudo}, sense 1.  An artificial
   identity created in cyberspace for nefarious and deceptive
   purposes.  The implication is that single person may have multiple
   tentacles.  This term was originally floated in some paranoid
   ravings on the cypherpunks list (see {cypherpunk}, and adopted
   in a spirit of irony by other members. It has since shown up, used
   seriously, in the documentation for some remailer software, and is
   now (1994) widely recognized on the net.