I seen Greg Mutt first after Avatar was released, he is a very lifelike anthropomorphic CGI Dog. At the time I though it was done by some Hollywood guy who had too much time on his hands, but turns out it is a short film company in Wiltshire UK called BustyKelp who are mainly know for their work on commercials.
The reason why I know this is because AudioMotion the tool they use has been using Greg to promote their tool. I just hope they make more videos now the secret is out, because Greg is cool.