I'm unsurprised Douglas Trumbull was behind the Close Encounters effect since his work on 2001: A Space Odyssey captured his earliest experiments filming tanks of liquids with fluids added. They were fairly effective in Kubrick's film when they appeared to resemble fantastic nebulae, globular clusters…
(And never mind the mind-bending cleverness of how the slit-scan shots were created for 2001.)
In fact, ha ha, when I was a teen, I set up a window pane as level as I could with a Super-8 camera beneath pointing up. I added water to about an inch in depth (about all I could manage for the window frame) and then poured milk in to create the cloud effect.
I don't have a recollection of seeing the resulting footage, making me wonder if I bothered filming it. Perhaps from the camera point of view all I got was reflections—or perhaps the whole thing was underexposed. Regardless, it was fun to be young and experimenting like that.
My best low-budget effect (not counting the stop-motion animation I experimented with—of course) was when I set my Super-8 camera upside down on a tripod outside at night. I had a piece of glass (the same glass window frame?) and had painted the silhouette of a house in black paint. The windows of the house were left clear but with white paper backing.
The camera was set up to film the glass-painted house outside at night with the sky/trees/stars that were outside as a natural backdrop through the glass. With the camera rolling I had a small light on behind the glass that made the windows of the house appear to be on. I turned it off after the camera rolled for a few seconds. Then I briefly kicked on a very powerful light that caused a quite a flash behind the silhouetted house.
The last thing to film was a thread I had hanging behind the glass that I set on fire with a lighter. It quickly burned up the thread as the camera rolled.
When the film came back I flipped it around end for end, splicing it back into the final roll of film. The inverted camera footage was now right-side up but with the film playing in reverse.
And so the thread had become instead a flame like a meteor crashing to the ground—resulting in a bright flash. Seconds later the lights in the house come on.
I love your attempt at a practical to that level. I have one that I'm still working on with long exposure timelapse and motion control, but I just can't ever get my schedule to let me do it. I have models of flying saucers with little aliens at the helm that I've rigged up with LEDs connected to an Arduino. That also controls the motion control slider I have, and the camera shutter. The idea was to turn on the UFO lights for a very short duration while the shutter is open to keep from over exposing during the long exposure to capture the night sky in the background. There is no point in doing the shot, except just because. I have the problem of when I have free time, the weather is shite or the wrong time of the year for the part of the sky I want.
There was so much creativity involved and out of the box thinking about physics and time and optics, to craft something that in the end resulted in a nice optical illusion. Like a magic trick (interestingly, in German visual and special effects are (or were) also called "Filmtricks").
Now with CGI, everything is possible and paradoxically, that makes it more boring somehow. And sometimes practical effects still look better IMHO.
However, checking the authors "Top/Worst films of the year", being called the "Single Minded Movie Blog" seems fitting, and not in the way they think. Some of the worst movie takes I've seen hahahahh
The results weren't that impressive, but it was fun, as was all the Super 8 stuff. I kind of miss those times and I see at least one other poster seems to have similar recollections :)
To add another nice example of this effect, which is where I learned about it, is The NeverEnding Story (1984). There it's used for the "nothing" (https://www.youtube.com/watch?v=rPfQogtS2Eo) and also in the opening of the US release (https://www.youtube.com/watch?v=CCgfRC6gHtI). The original German release only had text on a black background.
It might not look the most realistic, but IMHO it still looks beautiful.