Hashovilo, circassian mythology.
Caucasian nations used to belive that there is a monster living on river banks, which is a dog-headed bull. The name of this monster was Hashovilo. He was afraid of people, but his magic could kill a man who dare to look at him.
Magic people of Isp, living in Caucasian mountains had found a way to block Hashovilo's magic. They took a dog and sewed it a head of a young bull, so they created anti-hashovilo, a creature which is not afraid of deadly spells. So, river banks became safe.