This article is classified "Partly real, partly fictional"
Hitchhikers may discover that many cultures have stories concerning a curious one-horned beast. This beast, called unicorn, monoceros, ki-rin, ki-lin, karkadann, etc., was often pictured with a dualistic nature -- the horn gave it great strength and yet the beast was gentle; it was very beautiful but impossible to tame. For European society on Earth, starting with the Age of Enlightment, the existence of unicorns was doubted. Before that, unicorns were an accepted fact based on their mention (later discovered to be a mistranslation) in the religious text known as the Bible. However, actual unicorn sightings were rare. There are several theories why unicorns are not seen. One is that they never actually existed as the fantastic creatures griffins, sphinxes, and phoenixes. Another theory is that the unicorns were never more than essences without corporeal presences. It is altogether possible, even probable, that unicorns can exist only in a non-rational environment. In which case, they can only exist where their existence is not appreciated. This means, if you want to see a unicorn, you can't want to.