I've never been charged by a Grizzly, but I shook hands with a black bear once. Been stocked by a cougar, lunged at by a rattler, and chased outta town by the jealous husband of a bearded lady.
The defender is a good idea, I bought one for the exact same reason. It's awesome piece of mind. And if you promise not to tell the Fuehrer, I'll admit to carrying a 9mm sidearm for extra security in Grizzly country.
As for the Bigfoot, my buddy and I heard one once. Sounded like a cross between a moose and Chewbacca. The smell was horrible!!! We had a bad feeling, like something was watching us, and we just pulled a 180 and got back to my truck ASAP, and went hunting 10 kms down the road.