In Peter S. Beagle’s The Last Unicorn, the unicorn takes the human name Lady Amalthea. The name is given to her by the magician Schmendrick after magic transforms her into a human woman while she is being pursued by the Red Bull.
As Lady Amalthea, she and Schmendrick enter the court of King Haggard, accompanied by Molly Grue. The disguise allows the unicorn to approach Haggard’s castle and investigate the fate of the other unicorns, who have been driven into the sea by the Red Bull.
The human transformation is more than a disguise. Lady Amalthea experiences mortality, love, fear, and regret—emotions that change her understanding of humanity and distinguish her from the other unicorns. King Haggard is the ruler who captures the unicorns, while Schmendrick is her magician companion and Molly Grue joins the quest.