Keep It At Magic
Ehehe ehehe hee, if obvious nervous laugh wasn't obvious enough----that was a nervous laugh. Human Blockhead is a stunt and should be kept in that category. Geek Magic is doing something odd or even shocking by means of deceptive methods, human blockhead does neither and can be a risk to yourself and by proxy whomever pays your health insurance.
Some material I'd recommend looking into is Andrew Mayne's content. I'm not sure if it was in his hook through arm effect that he taught a clever way to do the setup under someone's nose but that method could be used to help get into doing the Saw effect by Sean Fields. Another source for shock and generally odd magic would be from the dvd under the same name, Geek Magic featuring Thomas Medina. Browsing through the menus of my copy they teach everything from how to eat glass (the geek magic way), drinking motor oil or if you aren't afraid of Ebola----drinking spit, and even a very nifty card trick that will have spectators hoping away in fright. Furthering, if you're looking for something more unorthodox I'd suggest looking into some of Bizzaro's products. One product I love from him is the Helter Skelter products, I bought the pamphlet first and then the DVD. Though this does border on stunt there are methods to "safely" perform the effect.
Have fun and be safe. Happy Halloween,
Keo