This may be a long shot, because I only hazily remember one scene that I saw as a kid on the screens in a costco warehouse store. Must have been very late 80s or very early 90s. The scene:
Woman (or smooth-skinned male??) Kneeling down on the ground, face in her hands. Surrounded by troops, I think, inside a large warehouse/factory or something. When she looks up, her face has become all cracked/fragmented/metallic, and she starts "unfolding" (transforming) out into some big battle station like machine, and exchanges hostile fire while still continuing to morph.
...then I don't know, mom called me away! Always wondered what that one was.