Getter Rays (ゲッター線 Getta-Sen) are a fictional cosmic ray radiation, typically green in color, prevalent throughout the Getter Robo franchise. It is a mysterious source of energy that had a part in the evolution of life on Earth and possibly several other planets and realities.
Getter Rays appear to have been prevalent since the beginning of time. Millions of years before mammals evolved, when the dinosaurs walked the Earth, a shower of Getter Rays penetrated the atmosphere. This drove the dinosaurs to near-extinction, the survivors forming the Dinosaur Empire within the depths of the Earth. With most of the Earth’s surface thus emptied for the taking, the surviving mammals evolved under the influence of the Getter Rays, resulting in many life forms – including humans.