Cornum The Brass Horned Unicorn’s Story – In the Magical Elements of the Periodic Table Presented Alphabetically By The Metal Horn Unicorns, readers are briefly introduced to Cornum, the Brass Horned Unicorn. Cornum is one of the metal horn unicorns featured in the Journey To Osm collection of books by Sybrina Durant. Cornum is a unique unicorn with a special talent that sets him apart from all the others. While most unicorns possess magical abilities like healing powers or the ability to fly, Cornum’s talent lies in music. He has a horn that can sound like any musical wind instrument, and his notes can vary from soothing melodies to brassy, boisterous tunes.