Jan Nemec – O slavnosti a hostech AKA The Party and the Guests (1966)

Distinguished as being ‘banned forever’ in its native Czechoslovakia, Nemec’s film is a masterpiece of barbed, darkly sinister wit. As a biting satire of governmental and institutional power and with its astute observations of human nature and conformity, it is a film whose relevance continues to this day.
Considered the most politically dangerous film made during the short flowering of the Czech New Wave in the 1960s, this is its first-ever release on DVD.

Quote:
This experimental Czechoslovakian film seems disturbingly akin to the works of Spain’s Luis Bunuel. A group of happy picnickers runs afoul of Jan Klusak, a bullying sadist who has some sort of unbreakable hold over his followers. Klusak subjects the picnickers to a cruel psychological game, wherein he plays interrogator. The ordeal comes to a brief end when a stranger (Ivan Vyskocil) arrives, apologizes for Klusak, and invites everyone to an elegant, formal outdoor banquet. But the bizarre “fun and games” continue, ending with the group embarking on a fully armed hunting party in search of a missing guest. Built on the premise of unquestioning conformity, Report on the Party and the Guests (O Slavnosti a Hostech) was a typically iconoclastic effort from the husband-and-wife director-screenwriter team of Jan Nemec and Ester Krumbachova.
Hal Erickson, allmovie.com