With YELLOW, Director Neill Blomkamp packs so much into 4 minutes. It's a sort of teaser trailer for an upcoming movie, a movie that should have been made by now quite honestly, but hasn't been.
Yellow is a sentient android, developed to be a weapon, but escaping, and deciding to live and learn among humans. Forces are dispatched to locate and destroy him / it. However, we get the distinct impression that it might be a little too late for that.
One thing about this, as well as most of Mr. Blomkamp's short films is that they will make you wish they had been made into the full-length movies that they hint at.
Until then, this will have to suffice...