Sui generis
Sui generis (; ) is a Latin phrase that means "of its (his, her, their) own kind; in a class by itself; unique."
Pseudospeciation
Pseudospeciation, according to the "Oxford English Dictionary", refers to the tendency of members of in-groups to consider members of out-groups to have evolved genetically into different, separate, and inferior species to their own. The term was first used by Erik Erikson in 1966, according to his biographer, Lawrence J. Friedman. Dehumanization is one possible outcome of pseudospeciation, as is ethnic discrimination or genocide.