tentacle n.
A covert pseudo, sense 1. An artificial identity created in cyberspace for nefarious and deceptive purposes. The implication is that a 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, saner members. It has since shown up, used seriously, in the documentation for some remailer software, and is now (1994) widely recognized on the net.