There was a Sci-Fi series way back around the 60's which I really liked. It starred Roy Thinnes and was called "The Invaders" The neatest thing was when he would kill one of the aliens, their bodies would burn up which was explained as having something to do with their souls going back to their home planet.
Ah, The Invaders! As a girl I was terrified of that big tophat in the sky. And after seeing most of the series again as an adult, it held up surprisingly well for a low to mid-budget '60s scifi show.
I love how the the invaders would glow before they burst into flames. I think this happened because the process that molded their bodies into human form stressed them thermodynamically, so a big enough shock to the system would initiate the catastrophic exothermic reaction as their bodies sought equilibrium. And they burned completely because their skeletons were cellulose-based (wood, IOW).
Oh yeah, and the stories were usually inventive. I kept thinking that with just a little more thought & polish to the writing it could be a great series. (But maybe I'm looking at a '60s show thru jaded '00s eyes there.) And the theme music was too cool.
I personally thought it was the best scifi series of all time with the possible exception of the original Star Trek.
I remember it was a Quinn Martin production and they all had a similar appearance. Also true that it was not a big budget show but they really don't have to be as long as there is enough to do what has to be done.