The cerulean scarab is a hard-shelled beetle of a pale sky blue color and move seasonally in packs. They are thought to live exclusively in Imperial territory by many but actually can also be found in Gallia.
As their main diet is oak, during their mating season, they gather at Gallia's oak forests. After getting enough sustenance to breed, they change color leading many people think they are viridian scarabs. By the time they return to the Empire to spawn, their color has reverted.