If I did that after spending a whole weekeng on a "no" animation for a Pikachu, I would have come out proud af "HEY, I DID THIS! I'M SO GOOD AT ANIMATING PIKACHUS OMG"
That hasn't happened, and the gif it's almost 2 weeks old.
After the announcement he/she will probably come and say it.
Don't get me wrong i'm not saying it's fake. I'm just saying people will do worse than this to fake something.