It appears as if many people think he is copying, well let be rational here.
This was uploaded on march 15, 2015.
Thiers was upladed 2 days prior.
He most likley thought of the idea before it was uploaded, checked the workshop, and saw nothing cause it had not been made yet.
He then went into SFM and took some time and effort to animate it, that plus export sed animation + sound, Finaly he uploaded it to the workshop... 2 days too late...

In conclusion Yes someone already made it, However it was not copying. I can tell you all from experience it takes more than 2 days to make an animation with this quality.