ORIGINAL: Stew99
I once used my Dremel jigsaw to cut a thick piece of plastic. What I didn't realize was that the friction heat of the blade was fuzing the plastic together behind the blade so that when I finished the cut I still had a solid piece of plastic. It would not even snap apart along the cut line.
I'm sure you could turn this accident into a new invention, the "Dremmel jigsaw plastic welder".