A unicorn is a mythical creature, similar to a horse, with a single spiral horn growing out of its forehead. In the Middle Ages, the unicorn appeared in paintings as a symbol of purity. Many people believed an animal like this really lived. In the Bible, most verses that refer to the unicorn emphasize its great strength (Num. 23:22; 24:8; Deut. 33:17). The biblical writer may have had the aurochs in mind. This horned wild ox was so large and powerful that no one could control or tame it (Job 39:9-10; Ps. 22:21; 92:10; Is. 34:7).