That's from Curse of the Were-Rabbit Wallace n Gromit, if ya didn't know. It's just a short clip in the movie, but she fires up the saw and it gives off a puff of smoke as she pulls the cord. Claymation, so somewhere there is a little 2" high saw that they made for it. She says something too as she fires it up, but I can't make out what she says. Nothing on youtube.