I've wondered on and off about these over the years – they are totally unrelated except for the fact that I would have seen each around the same time, early 1980's or possibly late 1970's, and probably on WLVI – Channel 56, Boston.
#1: Might have been horror, might have been jungle adventure, might have been sci-fi. I remember it being in color. I remember absolutely nothing about plot or characters, but the scene that burned itself into my retina involved a large cave, in which was a big primitive looking stone statue/idol. I assume this scene was at the end of the movie, because there was some cataclysmic event and the cave was shaking, fake rocks were tumbling in slow motion, and water was flooding in (I'm pretty sure it was miniature-scale water also filmed in slow motion.) I also seem to specifically remember the head of the stone idol toppling over and a jet of water shooting out of the neck. I was equally fascinated and scared by this scene.
#2: Definitely a horror film that was played more than once, because I remember being drawn back to it in spite of the knowledge that it was going to scare the crap out of me. The scene that has stuck with me was a woman (who may have been sporting a beehive hairdo, which itself was kind of disturbing) being attacked by a bloodsucking, flowering plant. I think this was also in color, because I'm pretty sure I remember seeing the flowers being on transparent tubes so you could see the red blood being drained out of the poor lady.
#3: Some kind of spy/sci-fi movie, featuring people either trying to escape or break into some kind of high-security compound. The particularly traumatizing moments in this film were: A guy getting electrocuted while climbing a chain-link fence. (I think this was a twilight or night scene) and ESPECIALLY bad guys dressed all in black, hiding in closets and behind doors, and then OMG jumping out and stabbing people in the neck with a jet injector, either killing them or drugging them to be dragged away for further skullduggery. I was afraid of closets and potential lurkers-behind-doors for a long time after this one, and I still get a little freaked out by any film or T.V. scene involving jet injectors. I remember the costume/clothing looking pretty contemporary, so my guess is this was a late ‘70s production.
Thanks for any and all possibilities you good people can suggest!