Deer can be surprisingly aggressive. A long time ago, when my parents ran angus cattle, we closed our farm to hunters for awhile and the population got pretty thick. The bigger bucks got so feisty during rutting season that we had trouble one year with a couple actually goring cattle that got in their way. We let a few friends and neighbors hnt on the farm real soon after that and never had the problem again. Course that wouldn't happen this time a year, but a mother doe can hold of an inexperienced hound quite readily just by stomping and blowing.
Also, could you have been in a horse pasture? Horses can scare off a hound that isn't used to them pretty easily.
Just in case it might have been a Bigfoot, here's a link to Bigfoot sightings by geographic area:
http://www.bfro.net/GDB/
you might want to check to see if there have been any recent sightings near you
