What is "bonnacon"

n. A medieval mythical bovine creature with huge curved horns that emits burning dung.

The bonnacon (also called the bonacon or the bonasus) is a mythical animal from the region of Macedonia. It has curled horns and when startled sprays acidic dung that burns on contact with skin "like a kind of fire". The legend may be based on a type of bison in reality. Some suggest that it had some resemblance to the European bison, which became extinct in the wild in 1919. A supposed representation of it appears on the coat of arms belonging to the Hollingshead Family, possibly alluding to a legendary confrontation between one of their ancestors and this beast.

The animal was described by Pliny in his Naturalis Historia: "There are reports of a wild animal in Paeonia called the bonasus, which has the mane of a horse, but in all other respects resembles a bull; its horns are curved back in such a manner as to be of no use for fighting, and it is said that because of this it saves itself by running away, meanwhile emitting a trail of dung that sometimes covers a distance of as much as three furlongs (604 m), contact with which scorches pursuers like a sort of fire."

The bonnacon is also mentioned in the Aberdeen Bestiary.