Who is the hat man?
He is the figure in the round brimmed hat, usually with a mustache. The game never gives him a name or a backstory. The news only ever asks the question: WHO IS THIS HAT MAN?
That is the joke. The station does not need to know who he is. It only needs a face it can turn into a headline.
When he appears
The hat man shows up after the park reaches total hate. He is easy to miss if you are still filming the crowd. When he appears, the broadcast pivots from the hate chain to the hat question.
This is the fork between the Hat ending and the Eyes Closed ending. Photograph him and the park wants hats. Ignore him and the panic burns out.
The hat craze
Once the hat man is on air, the park copies him. Hats spread through the crowd and the headlines move from Who is this hatman? to Hats are back, baby to Everyone wants a hat.
The route is a small satire of trend cycles. One person wears something, the camera notices, and suddenly everyone needs it. The ending card calls it someone finally noticing the hat man in time.
Hat man vs. the Star
The hat man is not the Star. The star is a spiky-haired square who becomes famous by screaming, then gets sunglasses and a crown. The hat man is already dressed for attention and becomes famous simply by being noticed.
Both are ordinary figures the news turns into celebrities. The difference is timing: the hat man appears when the park is exhausted by hate, while the star is created out of a single caught scream.
Why he is the trend
The Hat ending is the most-watched route right now because it pays off a mystery the game sets up early. The opening image asks WHO IS THIS HAT MAN? and the route finally answers it with a park-wide hat craze.