After the radioactive storms on Sollgel Island transformed the man-sized Kamacuras to giants, the world was stunned to see the insects descend on a small mountain and unearth a mammoth egg. The mantis creatures immediately smashed the shell, revealing within an infant Godzilla. The ravenous insects were about to gorge on the helpless Minilla, when Godzilla stepped in, blasting the creatures into full retreat. Then, in an act of benevolent heart, Godzilla adopted the baby as his own. Teaching the growing Minilla how to belch its fires and survive on the harsh lands. However, their survival was put to the test when the gigantic black spider, Kumonga, crawled from the brush. Only under the combined flames of each monster did they burn the vile existence of the arachnid away.

Following the defeat of Kumonga, the scientists of the island caused a blizzard to hit the once tropical shores, thereby forcing Godzilla and Minilla into hibernation. After their forced hibernation, it's assumed that the monsters found a new home in the South Pacific, a place dubbed Monster Island. It is here that children of Japan dreamed of. Some even imagining themselves to be friends with the little creature, and help see it through battles with a cat like ogre, Gabara. However, following the island's decimation in 1973, it's assumed that the monsters again relocated, this time to a forced habitation established by humanity on the Ogasawara Island chain. To a place called Monster Land.

Later, near the dawn of the 21st century, Minilla, along with the rest of the Monster Land's inhabitants, were taken over and controlled by an invading alien race. The Kilaakian used the monsters to carry out tactical strikes humanity, but were soon foiled. Not even their last ditch monster, King Ghidorah, could turn the tide, as Minilla helped in the defeat of the space monster once and for all.