The National Lobster Hatchery uploaded this incredible sped up footage of a molting cobalt blue crayfish (Procambarus alleni). Watch as it wriggles to free itself of its outer layer. From Reference.com:
Crayfish molt because they must shed their hard exoskeletons and grow new, larger ones as their size increases. During the first year of life, a crayfish molts six to 10 times. This number decreases to three to five times during its second year.