Gezora was first seen in the Toho movie titled "Space Amoeba". The kaiju was created by an alien virus infecting it. Transforming a normal squid into a 30 meter tall monster. The Kaiju went on killing sprees on native islands with little to no defense against the massive creature.
But the natives covered the beaches with flammable liquid. When the monster made another assault on the beach the natives cased torches. Engulfing the kaiju in flames and while in the chaos Gezora retreated back into the depths of the ocean. But the damage was fatal and the amoeba left the dying Gezora on the ocean floor.
Godzilla: Rulers of the Earth
Gezora is the third Kaiju to arise from the ocean and attack a aircraft carrier along side with Manda. They are both under the control of an alien armada planing to invade Earth by using it's local kaiju.