|Behind the scenes|
Insectosaurus was a one-inch grub transformed by radiation into a 350-foot (106.7 meters) tall monster that attacked Tokyo. He was captured in 1969 and formed a close bond with the Missing Link, who is the only person that can understand him.
Insectosaurus originally was nothing more than a simple grub with no unique characteristics, but after his mutation he donned an almost mammalian-like appearance similar to that of an orange hamster with a massive overbite, four pincer-like arms, antennas, two stubby feet, and a short reptilian-like tail. Insectosaurus is a massive creature in size even dwarfing the giant Ginormica. He is seen in the movie using his powerful pincers to pull the bridge back in place in the Golden Gate fight seen. Not only can he do that, he can also shoot sticky web substances from his nostrils that were used only on the Alien Robots eye to stop it from reacting for a short time so the other Monsters could get him and Ginormica (Susan Murphy) to the Golden Gate Bridge. Although of his big physique, he is actually a baby. When he walks, he does that in a dinosaur-like fashion and is very slow. Sometimes he doesn't know what to do so he is mesmerized and navigated by a helicopter carrying a light infront of Insectosaurus causing him to stare at it and follow where it goes. When that happens, the pupils of his eyes grow almost as big as the size of his eye making him look much scarier than he actually is.
After his metamorphosis near the end of the film, Insectosaurus' appearance is changed to that of a more butterfly-like creature (similar to Mothra of Godzilla fame) while still possessing his hamster-like face, furry body, massive overbite and reptilian-like tail. He's been renamed to Butterflysaurus.
Insectosaurus makes a cameo on the Monster Bay stage, destroying a bridge.
- He dressed up as Elvis in Mutant Pumpkins from Outer Space.
- He is the only featured team monster character to not appear in Monsters vs. Aliens (television series)
- He believes the Missing Link to be his father.
- The relationship between Link and Insectosaurus was based on the film King Kong vs. Godzilla.
- This said relationship is both similar and opposite of owner Sta'abi and pet Vornicarn.