Plan 9 is good, but "Glen or Glenda" is the true masterpiece. The famous sweater renunciation scene may well be the greatest 45 seconds of celluloid ever. The first time I saw Glen or Glenda in a movie theater I became physically hysterical, and couldn't stay to the end, and missed the sweater scene. Later, when I came for the second show, I finally got to witness the full unfolding of the creator's genius. I have seen it dozens of times, and it remains an awesome testimony to the complete weirdness possible in the human mind.
yours, Peter T.