That upload is much clearer than the one linked at the website above. Same uploader though. Definitely not a bear. You can stop it and see a very long arm no bear would have.
The very long arm is caused by leaves in the mid ground making it look like an arm. It’s a solid black blob, like a normal black bear.
Have not read the rest of the replies so please excuse me if this has already been suggested, but, it might just be a bear running off with an animal limb in it jaws. Just playing devils advocate, but I must say that it does give me the willies when I see it.