The odyssey of Mr. Garrison throughout the run of South Park has been one of its greatest subplots. But throughout the earliest days of the series, Mr. Garrison's constant companion was a puppet named Mr. Hat. And while he has long been gone from the series, Mr. Hat left a lot of answered questions behind.
In the first episode of South Park, Mr. Garrison appeared as the the 3rd Grade teacher at South Park Elementary. He was, and still is, an incredibly inappropriate and vile human being. As an educator, Garrison spent more time teaching the kids about reruns of The Facts of Life than he did the actual facts of life. He eventually became the 4th Grade teacher and then the President of the United States.
While Garrison is generally a reprehensible human being, one of the few relatable aspects of his personality would be his confused sexuality. It became quite apparent that Mr. Garrison was a closeted gay man who could not come to terms with who he truly was inside. That uncertainty plagued Garrison throughout the run of the series, though he did seem to be at his happiest when he finally accepted his homosexuality.
But before that happened, Mr. Garrison had Mr. Hat. He was a puppet with a beard and a red top hat who said and did the things that Mr. Garrison couldn't. Much to the chagrin of the kids in his class, Mr. Hat also helped teach. It generally didn't go very well. As with all things in Garrison's life, his relationship with Mr. Hat soured. For a time, Mr. Garrison replaced Mr. Hat with another puppet named Mr. Twig, who was literally a twig with a shirt.
That's when things got really weird. Mr. Hat went on his own adventures, somehow popping up in a sauna with Bret Favre without anyone's help. That's not the only time something like that happened — Mr. Hat once went to a KKK rally on his own because Garrison didn't approve. He also repeatedly tried to kill Mr. Twig. There was even one time that Mr. Hat actually kicked Mr. Mackey's butt on his own, though that doesn't seem particularly difficult.
Mr. Hat's biggest solo play was rescuing Chef and Mr. Garrison from jail. He somehow attached a chain to the bars in the cell window to an SUV, then used the car to yank said window out of the wall. Even if viewers accepted the fact that Mr. Hat could somehow get around on his own, he was only a few inches tall. He could not have reached the pedals or have seen over the steering wheel to drive. How he pulled that entire jailbreak off is a total trip to think about.
Early on, it was easy to write off the things Mr. Hat said and did as subconscious extensions of Mr. Garrison. But once he started operating on his own without anyone's assistance, it became increasingly difficult to explain his actions. Garrison was in a jail cell when Mr. Hat perpetrated the jail break. The reality is that he could not have helped Mr. Hat at all. As usual, fans were left with way more questions than answers.
The final episode featuring Mr. Hat as a regular part of the series aired in 2002. His only other meaningful appearance was in a 2010 episode where he played a part in Cartman finding out about his true lineage. As such, South Park has never fully addressed who or what Mr. Hat actually is. But given the sheer number of aliens, demons and assorted creatures that have popped up on this series, anything is possible.