Bah, finally have a chance to post.  Well I must say it was great to meet everyone and if I was a bit of lurker and not much of a conversationalist... Well it's how I am  Had tons of fun playing Munchkin with everyone it's been at least 2  or 3 years since I played last.  I must say I am saddened to have my theory of the temple dog/foo dog distinction killed, however when I had him sign my books he confirmed a tidbit about the Blackstaff.  The Blackstaff functions as a buffer or filter that catches and absorbs/eats the taint of the black magic while powering itself off the soul of the user.  It is, as described in the book, a living thing and practically sentient.  The tendrils advancing into and up the user's arm are more aggressive and hostile rather than pulling out the taint.  Woot.