If you are not familiar with the works of Peter Watkins, you really should be. Almost all of them are fake documentaries, but by no means funny ones. His film about nuclear war and it's aftermath, The War Game, is so incredibly grim and depressing that the BBC, who commissioned it, refused to show it for decades.
I think this film is scarier. It definitely feels more real.
Synopsis:
In 1970, the Vietnam War is escalating and President Richard Nixon has just decided on a secret bombing campaign in Cambodia. Faced with a growing anti-war movement, President Nixon decrees a state of emergency based on the McCarran Internal Security Act of 1950, which authorizes federal authorities to detain persons judged to be a "risk to internal security".
Members of the anti-war movement, Civil Rights Movement, and the feminist movement, as well as conscientious objectors and members of the Communist Party, mostly university students, are arrested and face an emergency tribunal made up of community members. With state and federal jails at capacity, the convicted face the option of spending their full sentence in federal prison or three days at Punishment Park. There, they will have to traverse 53 miles of the hot California desert in three days, without water or food, while being chased by National Guardsmen and law enforcement officers as part of their field training. If they succeed and reach the American flag at the end of the course, they will be set free. If they fail by getting "arrested", they will serve the remainder of their sentence in federal prison.
European filmmakers follow two groups of detainees as part of their documentary; while Group 637 starts their three-day ordeal and learn the rules of the "game", the civilian tribunal begins hearings on Group 638. The filmmakers conduct interviews with members of Group 637 and their chasers, documenting how both sides become increasingly hostile towards the other. Meanwhile, the film crew documents the trial of Group 638 as they argue their case in vain for resisting the war in Vietnam.
Almost all of the actors were unknown and most of the dialogue was improvised. The people being punished were real activists at the time and the people doling out the punishment were real conservatives, so the whole thing feels very believable.
And it feels like it's something that could still happen.
Trailer: https://www.youtube.com/watch?v=X04-bpHCCCU
Full movie on YouTube: https://www.youtube.com/watch?v=4bRMMdaQ790