crustacean / crustation [krʌˈsteiʃən]
crustacean – n. & adj. – n. – any arthropod of the class Crustacea, having a hard shell and usually aquatic, e.g., the crab, lobster and shrimp; adj. – of or relating to crustaceans
crustation – n. – 1. the act or process of forming a crust; 2. a thin coating layer; deposit