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 battle Monster on the Golden Gate Bridge. Although of his big physique, he is actually a baby, but that is not approved other than he cannot talk. When he walks, he does that in a dinosaur way and is very slow to walk. Sometimes he doesn't know what to do so he is mesmorized and navigated by a helicopter carrying a light infront of Insecto causing him to stare at it and follow where it goes, also it helps keeps him stable and be amazed at the sight. When that happens, the pupils of his eyes grow almost as big as the size of his eye making him look like a big scary looking monster, but really he is the cutest thing in the film! He cannot hear what the other monsters, aliens and humans are saying (Apart from the Missing Link) so that makes him a useless (almost), powerful, fun, cuddly Monster.
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 got back at Galaxhar in Spongebob and friends go home on the range, where he rammed into Galaxhar's wicked Jack form, also where he met spongebob for the first time, instead of Spongebob and monsters vs. Aliens, which was canned due to copyright. he joins in spongebob and friends meet dinosaur. he's like, well, a big, i mean, really big brother to the louge.
He is a parody of Japanese Toho Monsters, he is inspired by Mothra from (Mortha and Godzilla, 1964, among others). Mothra was a giant moth who appeared both as a larvae and as a full-grown creature.
He thinks that the Missing Link is his dad.