Bicorns are dangerous cow-like creatures. At least one of its two horns are a required ingredient for Polyjuice Potion. Their horns are shed annually and are then gathered when the Bicorn is not looking.
In mythology, the Bicorn (also known as the Bicrone or Bulchin) was a creature with two horns. It has the reputation of devouring kind-hearted and devoted husbands. It is described as very fat and good-natured. There was another beast called the chichevache which fed on obedient wives, but it was said that the "famished beast" was thinner than the bicorn, for "its food always fell short.