Phasing

Phasing was the process by which Koturians transform and take on a new physical appearance during their marriage ceremony, beginning prior to the moment of the ceremony itself. Several internal and external factors cause their metabolism to go into overdrive to produce the change. It's a sacred rite of passage to Koturians: upon marriage, the newlyweds are the first to see each others' new faces as they begin their lives together. However, the process only happens once during a short window in the prime of a Koturian's life. (PROSE: Something Borrowed)