Insectosaurus

Insectosaurus is one of the main characters of the movie. According to both The Art of Monsters vs. Aliens and character designer Craig Kellman, Insectosaurus is female. Before transforming into a butterfly with feminine characteristics, she was mistakenly believed to be male by the Missing Link.

Insectosaurus was originally a one-inch (25.4 mm) grub who was transformed by radiation into a 350-foot (106.68 meters) tall monster that attacked Tokyo. She was captured in 1969 and formed a close bond with the Missing Link, who is the only person that can understand her. She transformed into a butterfly in 2008.