unicorn performing at the Castle of Zork (c. 900 GUE)
    Stonewall Flathead on a war unicorn
    A Painting of a Unicorn (painted pre-945 GUE)

The unicorn is a magical snow-white horselike beast with a single slender horn in its forehead, the color of fine ivory, with a deep spiral groove. It is good luck to kiss a unicorn's horn, but woe to any fool who harms one. While nonchalant and affectionate to those who are kind to them, those who dare to threaten them are met by an un-unicorn-like display of temper, usually being impaled by the tip of a pointy horn. Unicorns abhor being wet, especially soaked by rainstorms. The unicorn's speech is but neighing to the naked human ear, but some have been able to communicate with humans through telepathy.

The royal army at Flatheadia disrespected these graceful animals by using them for combat mounts against their wills. While there were no wars in the lands, these unicorns were free to roam the Great Underground Savannah near their stables atthe base of the Great Underground Mountain.

Most unicorns have fled to the Plane of TransInfinite Splendor, where they enjoy a carefree existence free from the injust cruelty of man. The unhappy few left behind are eagerly sought by zoos and private collectors. One such private collector in Mizniaport actually had his last unicorn freed in 966 GUE by a peasant who was on a quest to recover the Coconut of Quendor. While many unicorns are frequently seen wearing a gold key on a chain around their necks, all of those dwelling in the Plane of  Splendor have them. The mystery of these keys has yet to be explained.

The unicorns living on the Plane of TransInfinite Splendor are civilized, yet fear the invasion of the unwelcomed "earth-dwellers" as they have grown accustomed to calling humans. For they have refused to allow their children to know the pain which they had suffered by unrelenting men. All intruders are greeted by a troop of unicorns in full military regalia. The first human to visit this Plane was the same 966 peasant. After being show a horrible vision of what would befall any who dared to violate their solitude again, the peasant was told to describe this fate to the rest of the "earth-dwellers." Any human visitors after that point were humiliated by having a painful metal bit forced into their mouth, as they hauled wagonloads of overweight, aristocratic unicorns. The rest of their lives were spent pulling this laughing burden in a small circle, silent and powerless as cruel taskmasters whipped them over and over again, with infrequent stops for dirty water and oats.

Despite that most unicorns had fled to these planes, an unknown Festeron resident in the Second Age of Magic had a unicorn named Harry as a pet, who was very loving towards his master.