This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Forest Bull (Medieval Bestiaries)
The Forest Bull, also known Ethiopian Bull and Ethiopian Forest Bull, is an animal from ancient and medieval bestiaries. According to Pliny the Elder, they were a breed of ferocious, tawny cattle living in Ethiopia, with mouths gaping open to the ears. Their horns, like a Yale's, could swivel in any direction. To fight, they raised them, after which the horns remained in this position.
According to Aelian, they were called "flesh eaters" and were the most ferocious and savage of all animals. They were twice the size of regular bulls and could run at great speeds. He cites their hair as being red. No weapon could physically hurt the bulls, be it spears or arrows because even iron deflected from their skin. The forest bulls hunted herds of wild animals and horses.