Unicorn is a legendary creature. It has been described as a beast since ancient times. It has a huge, sharp, spiral horn on its forehead. Unicorn is depicted in the ancient seal of the Indus Valley civilization and mentioned by many ancient Greek writers, including ctesias, Strabo, Pliny the younger and Aelian, on the basis of natural history. The Bible also describes an animal, re'em, that some versions translate into unicorns.

In European folklore, unicorns are often depicted as white horse or goat like animals (sometimes with a goatee beard) with long horns and even hooves. In the middle ages and the Renaissance, it was usually described as an extremely wild woodland creature, a symbol of purity and elegance that can only be captured by virgins. In the encyclopedia, it is said that its horn has the ability to make poisonous water drink and cure diseases. During the middle ages and the Renaissance, the tusks of the narwhals were sometimes sold as unicorns.