The Light Ray Robot was a crystalline robot, made out of a special glass that made him completely invisible. He was later kidnapped by Skunk Kusai and misused for robberies and petty crime. Light Ray is adapted from Electro in the manga, and Zero the Invisible Robot from the 1963 series. Light Ray appears exclusively in the episode "The Light Ray Robot" of the 1980 series.
Light Ray was made entirely out of a special material called PH Glass, making him only visible under polarized light. Light Ray was constructed for aesthetic appeal and to showcase the versatility of PH Glass. When lit up, he looked like an angelic blue boy in his early teens, with short hair, a belted jumpsuit, and tall boots.
The Light Ray Robot debuts at Japan's National Robot Pavilion Exhibition, where he is put on display in the main hall under polarized lights. Light Ray later wins the Robot Art Award, but when his lights are turned on again, he is gone. In the following days, jewellery stores and banks report being robbed by an invisible entity, which some assume is a ghost. However, Skunk Kusai has just broken out of jail and has convinced Light Ray to do everything he says.
After Higeoyaji calls Skunk a liar, Skunk decides to show off Light Ray in a public park. Astro crashes the meeting by pure chance, thus getting in a fight with Skunk's men and Light Ray. That night, Light Ray visit's Astro's window, curious about how Astro seems to have hard legs like his own, and not those of humans. Astro realizes that Light Ray is not malevolent and only innocently taking Skunk's orders, but an attempt to have him do good deeds only makes Light Ray distraught.
The next day, Light Ray visits Astro's Christmas party. Higeoyaji arrives dressed as Santa Claus, and gives Light Ray a tracking device in a necklace, and paints his legs bright red. Light Ray immediately runs back to Skunk's warehouse; Skunk's men are unable to get the paint off, and an enraged Skunk gives Light Ray a bomb to take to Higeoyaji's house. Light Ray likes the ticking of the bomb and decides to keep it for himself. Shortly after, the police bust Skunk's warehouse, and Light Ray gets lost in the night with a live bomb.
Light Ray is soon located walking through a forested area with the bomb, heading towards a prestigious national hospital. The police are forced to shoot Light Ray with a high impact energy bolt, detonating the bomb a safe distance away from the hospital, which unfortunately kills him instantly.
Light Ray was childlike and naive, due to being sheltered and handled as a piece of artwork. This unfortunately led to him easily being lured away by Skunk and talked into performing crimes. Light Ray was even unaware that he was a robot, only realizing the difference between humans and adults after he and Astro briefly fight. Astro attempted to teach Light Ray the difference between good and evil acts, but this was impaired by Light Ray's inexperience with social norms. He could be very gullible and overly trusting.