Implanted RFID Chip

I came across this item recently, regarding implanted RFID chips acting as a 2nd factor of authentication.

http://connectid.blogspot.com/2008/10/is-this-2-factor-authentication.html

I don't think there's any doubt that this is a form of multifactor authentication, as disturbing as it may be... The interesting, though academic, question is this: is the RFID chip then something that you have or something that you are?