When it comes to self-defense, skunks and spitting cobras have nothing on the bonnacon. If threatened, it fled. While fleeing, it defecated. Violently. According to Pliny the Elder, the excrement voided the animal’s body with such explosive force that it could hit targets more than a football pitch away. Contact with its dung was said to burn like a kind of fire, scorching hunting dogs and anyone not equipped with protective gear. (There is some uncertainty whether the weapon was liquid or gaseous, super-heated or acidic.)

As with many mythical medieval creatures, the bonnacon was a composite: the head of a bull, the mane of a horse, and its horns were “bent inwards upon each other, as to be of no use for the purposes of combat”, writes Pliny. First described by Aristotle (as a possibly distinct animal called the bonasus), the bonnacon was resurrected in medieval bestiaries due to the influence of Pliny’s encyclopedic study of the ancient world. The Natural History locates the dungy bull in Paeonia — roughly today’s North Macedonia — but later writers elaborated its ethology, rehoming it in Asia.

The twelfth-century Aberdeen Bestiary, for instance, expanded the projectile’s devastation to an area of three acres and blamed the bonnacon’s “convoluted” horns for its upset stomach: “the protection which its forehead denies this monster is furnished by its bowels.” Other naturalists seemed to borrow the bonnacon’s properties when observing novel fauna: Polish onagers, as studied in the thirteenth-century by Gervase of Tilbury, guzzled water when threatened, expelling a blinding “deluge from their nostrils”; Bartholomaeus Anglicus described a nameless Bohemian beast in the eleventh century that “shoots at hunters or dogs coming too close to it . . . this water horribly removes hair from and scalds whatever it touches.”

While many creatures in medieval bestiaries are laden with Christian symbolism, the bonnacon’s appearance seems to be more like a gag — for both its victims and audience. Browsing the image’s gathered below, we might not know whether to laugh or duck. Hunters with ineffective shields gaze at the viewer, as if pleading for our assistance, while choking on stench. The bonnacon rarely seems in pain, more so disgusted at what he has been made to do, or taking visible pleasure in his pollution.