In 1984, Timothy Zell patented a surgical procedure to make a unicorn of a cow, antelope, sheep, or goat, essentially by transplanting the horn buds.
In the patent abstract Zell notes that he’s following on the work of University of Maine biologist W. Franklin Dove, who apparently spent several years in the 1930s pursuing the same endeavor; in May 1936 Dove published an article the Scientific Monthly with the notable title “Artificial Production of the Fabulous Unicorn.”
Zell’s improvement consists in transplanting the buds early, before they have become attached to the skull. But he notes also that he wants to create a unicorn with “a higher mental capacity and greater physical capabilities” by positioning the horn over the pineal gland. “Tests have indicated that transposition of the horns of the animal to form a unicorn with the single horn being positioned over the pineal gland has rendered a more intelligent and controllable animal.” Sounds like he was planning something specific.