Haxan
1922
Häxan (1922), Benjamin Christensen's witchcraft lecture that turns into a sabbath. Banned in America for years. Watch the silent horror film free online.
It opens like a lecture. Woodcuts, a pointer, a patient walk through medieval demonology, and then Christensen stops explaining and starts staging the things the woodcuts only hint at: the sabbath, the confessions, the nuns coming apart in the chapel.
He wrote it, directed it, and played the Devil himself, horned and lolling and clearly enjoying it, with the look built out of Hieronymus Bosch. Svensk Filmindustri put close to two million kronor into it, which made it the most expensive Scandinavian silent film ever made.
American censors banned it outright and the studio never got its money back. A hundred years on it is free, and still the strangest thing anyone has filed under horror.
Free to watch via internet-archive.