Here's a quick and dirty example of applying the first method that I mentioned (plus some enhancements) to the robot, Gort, from the original "The Day The Earth Stood Still" movie.
1. I started with a small, circular red dot.
2. I then stretched it horizontally and shrank it vertically.
3. Made a copy and applied Gaussian blur to the copy, then adjusted the opacity of that layer to about 50%, and merged it with the result of step #2. Adjusted "Levels" to taste.
4. Repeated step #3 with successively larger blur radii a couple more times,
5. Adjusted the width and height as appropriate for Gort.
6. Turned on Gort's layer. Cloned away the bright lights in the background because they would interfere with the red light streak.
6. Switched the blending mode of the final result for the red light streak to "Dissolve".
7. Added some fun rainbows, rays of light, some large radius unsharp masking -- things to make the image look not so sterile.
Before:
View attachment 56957
After:
View attachment 56958
HTH,
Tom M