In case you haven't seen the fanmade movie, Godzilla: Wrath of the Hybrid, I will explain. A fleet of aliens planning to invade Earth brought SpaceGodzilla back from the dead to help them. In the battle that followed, Godzilla was killed, but his energy passed on to Godzilla Junior, who defeated SpaceGodzilla.

DNA samples were taken from SpaceGodzilla and the original Godzilla to create the almost unstoppable hybrid, Kudajira. After an epic battle with Orga, who the aliens sent down as a distraction, Godzilla and Mechagodzilla fought Kudajira, who was easily winning. Mechagodzilla was destroyed, and Godzilla was very badly injured and dying.

Only because the guardian monsters: Mothra, Rodan, and Anguirus gave him a massive power surge did Godzilla finally triumph and destroy Kudajira along with the alien warship.