A horn, of course! cloved hoofs, a lions tail and a goats beard, sounds odd but true I agree with the answer above. but they left out one thing; magic.
The antonym of a unicorn could be a horse.
Either half horse half Unicorn or a Unicorn or a horse. Hard to tell. A DemiCorn.
Unicorn
you get a unicorn
A horn.
unicorn
pony or unicorn
A Unicorn is a cross between a horse and a drunken douschebag from Denmark
Unicorn
Unicorn
A horse, of course.
a unicorn