A gamma-ray laser is a special kind of laser that uses gamma rays, which are a type of very powerful light. The gamma rays are fired at a target, which causes atoms to absorb the energy from the gamma rays, releasing more gamma rays in the process. This process continues with the new gamma rays released from the atoms being fired at the same target, which absorbs the energy and releases more gamma rays, and so on. The result is an intense beam of light (laser beam) that is so powerful that it can be used in many different ways like in medicine and engineering!