I'm going to come right out and say it: Sometimes, I'm a terrible person. More on that later
This is one of the last of the awesome toys your grandparents had that isn't banned yet. The device uses science and genius to create a ball of air that flies through the air and hits stuff. Let that sink in for a second it wasn't a mistake. So what it does is create a vortex ring (doughnut shaped air bubble) that is able to stay together over long distances (About 30 feet in calm air) that travels in a straight line until it hits something. You or an unsuspecting squirrel will actually feel as though something solid has hit you and then immediately harmlessly vanished. It's incredible and perfect for screwing with people, pets, or wildlife.
And now the story:
So in the neighborhood I grew up in there were a lot of squirrels that had over the years gotten far too used to people and cars and tended to get too close to both. The only remedy to this is to put the fear back in those little jerks without actually hurting them because I actually do like animals. That solution is right in front of you. Whenever I remembered and one of the local squirrels got too blasé about getting near people I'd give him a taste of air cannon. When the vortex hit them they'd just turn inside out for a moment and then scramble for the nearest tree. Yes I know that scaring the poor little creatures was bad (boohoo) but it was better than them getting to close to one of the local kids and getting hit by a rock.