I need some help, here; this is really bugging the crap out of me...

[Little Brown Fox]

It seems awfully finalized, though. And also, he seemed to have absolutely no qualms about destroying the competition, regardless, for all that he complained about it when it wasn't going to be him fighting, so he thought...

I'm mostly concerned about where it came from, and where it could be found if one were to look for it, besides that weird music video, anyways.

[Earthshine]

I think Tetsuwan Penguin might be on to something with it being part of a teaser/trailer which can have scenes not even properly fit into the actual movie. A good example I can offer is one of the Big Hero 6 trailers in which Hiro suits Baymax up and then when Baymax flexes all of the armor pops off and goes flying everywhere! Only parts of that scene got into the actual movie.

If all else fails have you tried asking the creator of the video where the image came from?

[Little Brown Fox]

It's on Vimeo, though. And I don't have an account on there. Plus, I think the video is a few months old by now... I seem to recall it being around four or more when I first watched it. Plus, no one else had made any comments, and I cannot even remember if comments were allowed or not.

Also, I do not know anything about Big Hero 6 all that much. I would like you to refrain from mentioning too much detail; I have not seen it yet and it's among the things I wanted to see.