Robot Monster (1953)

In Robot Monster, a monster from outer space, known as Ro-Man, threatens to destroy humanity. Ro-Man has been sent by an alien race to exterminate all human life. He uses various weapons, including a death ray, to attack humans and destroy their cities. However, a scientist named Professor Norton discovers a serum that can kill Ro-Man. With the help of his daughter and a group of survivors, Professor Norton sets out to save humanity from Ro-Man's evil plans.