Length: 2 meters
Mass: 500 kilograms
In the original Showa film Rodan, 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 a Rodan, who began to devour the comparatively tiny Meganulon. The event traumatized Shigeru and he briefly suppressed the memory.
The Meganulon return again in the Millennium film Godzilla vs. Megaguirus. During the testing of a weapon called the Dimension Tide, a giant prehistoric dragonfly enters the present due to the weapons ability to warp the fabric of reality. It deposits a single egg before exiting through the wormhole. A boy finds the egg and takes it with him when he moves to Tokyo. The egg starts oozing a strange liquid, so the boy throws the egg in the sewer. The egg, actually a mass of hundreds of eggs, splits up and starts growing. The eggs hatch into Meganulons that come out of the sewer to feed. They flood a portion of the city and moult on the sides of buildings, becoming Meganula.
Wingspan: 5 meters
Mass: 1 ton
After evolving from Meganulon, the Meganula flood part of Tokyo. Congesting in their hollowed shells, the creatures broke free and rose into the noonday sun. Thousands upon thousands swamped the skies, shielding out the very light that warmed the land. Cutting across the voids of the turbulent seas, the countless waves of snapping fangs and clawing talons found their prey. They attacked Godzilla, during his battle with G-Graspers. Many were killed by Godzilla and the Dimension Tide, but few managed to drain some of Godzilla's blood which they gave to their sleeping mighty queen, Megaguirus.
Length: 50 meters
Wingspan: 80 meters
Mass: 12,000 tons
The 2000 Godzilla film Godzilla vs. Megaguirus featured an extinct species of dragonfly, based on the Meganulon, as Godzilla's adversary. According to the film, Meganula and Megaguirus had originated in China during Carboniferous period. 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' descendant was created when a weapon that would send Godzilla into another dimension allowed a giant insect to arrive on Earth and lay an egg which would later be discovered by a young boy and then hatch into a Meganulon. Unlike most insect queens, which do not fight and instead merely lay the eggs, Megaguirus is a very powerful fighter and 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 energy Megaguirus receives from her victims apparently creates something of a link between her and who or whatever it was originally siphoned from.
Though this energy is important in keeping her life-force stable, she will sacrifice some of it in times of dire need when an adversary is proving rather stubborn: she will project the previously absorbed energy as a massive ball of plasma towards an enemy, it was Stock Footage in Godzilla Final Wars in the Beginning.
Megaguirus is also one of the few monsters known to show any form of expression, as it is shown with a malevolent grin during her battle with Godzilla before sending part of a building down on top of him. She was ultimately killed when Godzilla was able to intercept her stinger and destroy it, which enabled him to then attack her at will with both bare-handed tactics as well as with his nuclear beam attack.