I'm trying to find a movie that involves a guy who can turn into an alien type thing and fights people. He goes to this building/searching site to look for something from outerspace and it has to do with him turning into this fighting alien thing and then there is another guy with the same fighting thing and they fight at the end of the movie.
The movie was probably made in the 1990's.

Sounds like "guyver" with mark hamill

Yeah guyver