I think this alien movie was made sometime in the late 80s/ early 90s. I don't remember much about it except that at some point an alien disguises themselves as a school teacher and there's a scene where he or she writes strange symbols on a whiteboard. And his/ her eyes turn black.

The movie is not a comedy.

I seem to remember a lot of people with shaved heads trying to close a door with a blue light behind it and then diying.