Mark of the Witch (1970)
Starts off in the old days, with a witch placing a curse on the folks who are executing her. We've seen this a million times, so let me just point out that the witch does the most extreme overacting I've ever seen, complete with eyes and mouth wide open. Cut to nowadays (well, 1969 anyway) as a woman sings an odd a cappela chant, written by the lead actress in this thing, over the titles. She's a college co-ed who finds an old book of spells and takes it to one of the informal seminars about various kinds of spooky stuff held by a professor. Hey, guess what? Professor looks exactly like the guy who was part of the witch's coven, and who betrayed her. The students cast a spell from the book to attract witches. It's a darn easy spell, too. You just need some candles, wine, and rosemary. This results in the co-ed being possessed by the witch. (Oddly, the co-ed is not played by the same actress who played the witch.) She kills the professor's dog with magic, then makes him teach her about the modern world, explaining such strange things as telephones and coffee. (At this point the movie is like an odd, non-comedic version of Bewitched.) After zapping the professor's pet bird as another demonstration of her power, she goes off in the woods and chants some mumbo-jumbo. She goes on to drug a couple of students to control their wills, makes them pledge their bodies and souls to Satan, then kills them. At the end, the professor and the co-ed's boyfriend set up a timer to project a cross of light on her, just when she's performing some kind of ritual. This frees the co-ed, brings the actress playing the witch back, and leads up to the Shocking Twist Ending. It's a cheap little film, notable mainly for performance of the lead actress. While not exactly a good one, she does manage to change from sweet and innocent young thing to evil temptress in a reasonably convincing manner. Lots of bright colors, and the students look both extremely clean cut and 1960's groovy at the same time.
Warlock Moon (1973)
Begins with a woman walking around some spooky place with a candle, talking to somebody we don't see. Guy with an ax jumps out and we cut to the titles. Next we're at a college lecture, where the instructor informs us that incest is the most common form of deviancy (?), followed by a promise to talk about cannibalism next time. Foreshadowing! Our co-ed heroine is approached by a guy wearing a trench coat and a Groucho mask, who speaks in a fake French accent about some nonsensical spy stuff. Instead of telling him to buzz off, she puts up with this nonsense, and agrees to go on an outing with him. Mind you, they just met. That's how you pick up girls, guys! They find an abandoned spa/sanatorium place, wander around, meet the old woman who lives there. Guy convinces her to come back a couple of days later, but they have to show up in separate cars. This turns out to be a minor plot point at the very end, and also makes the viewer wonder why she has to plead with the guy to leave when she could just drive away at any time. A couple of creepy guys attack her, and the old woman and the guy try to convince her it was just her imagination. She foolishly agrees to stay the night, we find out the guy is in on the plot with the old woman, there's the ghost of a bride (played by the same actress as the co-ed), some kind of blood ritual at midnight, a store room full of body parts, etc. Our heroine escapes, gets busted by the cops when they find (or plant) marijuana in her car -- I told you it was a plot point -- leading up to our (pretty lame) Shocking Twist Ending. It's a pretty lousy movie. Notable for a scene in an empty swimming pool where the guy acts out an extended parody of a horror movie, playing both the monster and the creator of the monster, who rescues the co-ed but turns out to be a monster himself. Foreshadowing!