Rocket Propelled Tooth Brush is a technology tooth brush. It is stolen by Granny May in "Who's Your Granny?" after she decided she needed to do bigger and more technology-based crimes.
It seems to have been invented by Professor Tubing, as he is in the lab where it was stolen. He does have a little bit of screen time with his pet monkey, but he doesn't have any lines.
Professor Tubing (who first appeared in "A Game of Cat and Mouse") was the scientist who moved into Professor Boxleitner's lab after he became Dr. Two-Brains and left it.