In the fictional universe of the Gundam Seed series, the GENESIS laser cannon is a giant gamma ray cannon that directly fires out the energy of an atomic bomb. GENESIS stands for Gamma Emission by Nuclear Explosion Stimulate Inducing System. PLANT Chairman Patrick Zala had this Doomsday Weapon constructed. It was the major part of his plan to exterminate all Naturals, since he blamed every last Natural for the death of his wife. The GENESIS was equipped with all the latest technologies, Phase Shift Armor to protect it, Mirage Colloid, to cloak it from plain view and a Neutron-Jammer Canceler which allows it to run on Nuclear Power.
In Gundam Seed, GENESIS was fired three times: the first shot destroyed a great part of the Earth Alliance fleet, while the second shot destroyed several other ships and the moon base. The third shot was to be fired on the Earth. Fortunately, Athrun Zala got to the center of GENESIS with his nuclear-powered Justice Gundam and self-destructed it just in time. This caused a nuclear explosion that destroyed GENESIS. Only a little amount of energy from the third shot was used before GENESIS blew up and it only destroyed the Providence Gundam. Thus the Earth was saved.