You're most likely overestimating it's size. Most people do this when encountering an animal they know nothing about.
You don't say mountains and forests WHERE, but from your description, I'm think the US, which means a wolverine:
http://www.defenders.org/wolverine/basic...
While larger than any other weasel, they aren't quite as large as you think. But when they bristle their fur, they can definitely LOOK huge. They are typically fearless as they have few predators. Color of the fur varies significantly. Do an image search on them and you'll see what I mean.
EDIT: If it wasn't a wolverine, dog or wolf, you would need to get a picture, sorry. There are limited predators out there of that size.
It is nice scary story. There is only one animal the size of a grizzly and that is a grizzly unless you saw a rabid mutant moose.
A warg.
I live in the mountains and my backyard is nothing but forest and I've been seeing this animal. It looked like a wolf, but it was the size of a grizzly bear, a hunched back, long nose, green eyes like a cat, blackish fur, extended claws and a tail that curled up on its back. It didn't seem afraid of me even when I got my rifle and my hounds were barking inside the house. I had never seen nothin like it! and the night after I first saw it I heard scratching and whining outside my house, it sounded like a baby crying. it was very creepy, I considered my place haunted. the next morning I could see bite marks and claw marks on parts of my home. And after, I've been finding several dead animals with their insides ripped out on my property. what is this?
