Meganulon (メガヌロン, Meganuron?) were Mesozoic giant insects reanimated by mining operations in Kitamatsu village, Kumamoto Prefecture, in the 1956 kaiju film Rodan. (Presumably they are, like the titular daikaiju, from the Cretaceous Period.) The car-sized insects, which resembled overgrown earwigs, slaughtered several men before some were killed in a mine shaft. A mine collapse followed, separating engineer Shigeru from fellow miners and police. Before finding his way out of the mine, Shigeru witnessed the hatching of Rodan, who began to devour the comparatively tiny Meganulon.
The added death toll and still missing whereabouts of Goro prompt suspicion that the missing miner is in fact behind the series of killings. A hunch which is quickly dismissed as one of the Meganulon ventures into a local village to attack a couple, Kio and Shigeru, who flee to get help. Shortly after, the police arrive on the scene and ineffectively try and shot the giant insect down while it bids a hasty retreat back to its lair. The police are quick to pursue, but their weapons pose no threat to the thick carapace of the ravenous insect, whose deadly pincers take the lives of two officers who advance too close. The Meganulon then returns to the mine shaft, killing more innocents along the way.
With the killer finally revealed, and the seriousness of the situation grasped, the self defense force is quickly dispatched to the area to exterminate the threats. Armed with mountable machine guns, a few regiments of soldiers, along with Shigeru, march into the mine to hunt down the creatures. While searching for the Meganulon, Shigeru uncovers Goro's body, which had been dragged deep into the shaft. There is little time for grieving, however, as Meganulon start to emerge to fend off the intruders. The military shells the creature with machine gun fire, but to no avail as the carapace, once again, deflects the bullets. Out of options, Shigeru hitches a ride on a nearby mine cart, driving it down the shaft and directly into one of the Meganulon, killing the beast. With a small victory claimed, Shigeru attempts to retrieve Goro's body, but ends up being trapped as another Meganulon emerges just as a landslide blocks his escape. The large rocks continue to pummel the area, knocking Shigeru out and killing the giant insect.
Eventually, the young miner awakens, as Shigeru opens his eyes only to realize that he is now trapped in the Meganulon's lair. Even with the ravenous insects all around, Shigeru's attention is diverted to another object in the room: a mammoth egg. It's quickly discovered that the Meganulon weren't the only creatures awakened by the atomic tests, as the egg hatches to reveal a gigantic pteranodon called Rodan. The red hued monster flaps its still developing wings, as it spies the killer insects that are situated all around it. The beast wastes no time, and quickly begins to devour the nearby Meganulon, as Shigeru can only stumble backwards at the sickening sight. Once full, the infant monster spreads its wings and takes flight, leaving behind it the remnants of the once horrific insects while Rodan would soon prove a far more deadly adversary to the entire globe.Godzilla film Godzilla vs. Megaguirus featured Megaguirus (メガギラス, Megagirasu?), an extinct species of dragonfly, based on the Meganulon, as Godzilla's adversary. According to the film, Meganula (also Meganuera) and Megaguirus had originated in China during Carbiniforous times. The insects follow an odonatan life cycle of which the Meganulon is the nymph stage. After a hemimetabolic interim the winged Meganula moult and take flight. Megaguirus was in fact the chosen queen among the colony and allowed to grow to massive size. As such, she is one of few decidedly female creatures of the genre.
Megaguirus's decendant was created when a weapon that would send Godzilla into a black hole created a time-space distortion. This allowed a Meganula from Earth's distant past to arrive on Earth and lay an egg which would later be discovered by a young boy and then hatch into a Meganulon. Megaguirus has numerous abilities. At top flight speed she vanishes into a blur, enabling her to surprise an opponent from an unexpected quarter. This high-speed flight also produces high frequency sonic waves capable of shorting out nearby electrical equipment. Her sharp wings can even cut steel and concrete. Her large abdomen ends in a vicious stinger used to pierce into an opponents hide and drain energy from it. During this process, the opponent is incapable of launching any additional energy-based attacks upon her.
The Swarm usually starts from one large egg that houses thousands, possibly tens of thousands, of eggs. They then hatch into the larval form, the Meganulon. After eating enough food they shed their skin and become the imago form, the Meganula. This form flies far away and lays another egg, starting the process all over again. Although the Meganulon and Meganula do most of the work, they must have a queen. So the Meganula begin to gather energy and deliver it to the chosen Meganulon. The Meganulon will absorb the energy and grow into the cocoon form of a Megaguirus. After absorbing enough energy the cocoon will burst open and reveal a Megaguirus
- The Meganulon is an actual species of giant dragonfly that lived durring the Devonian Period nearly 300 million years ago. Of course, the real Meganulon never reached the size of the monster that appeared in Rodan or Godzilla vs. Megaguirus.