Freaks from mythology

 The Cynocephali is a race of dog-headed freaks.

Sources

The "cynocephali" is another races of prodigies described in medieval literature: Augustine, Isidore of Seville, Paul the Deacon, Adam of Bremen, and Ratramnus all reported on the Cynocephalae. Quoting St. Jerome, Thomas of Cantimpré corroborated the existence of Cynocephalos, in his Liber de Monstruosis Hominibus Orientis, xiv, ("Book of Monstrous men of the Orient").

Additionally, in Chinese record Liang Shu (History of the Liang Dynasty), the Buddhist missionary Hui-Sheng describes an island of dog-headed men to the east of Fusang, a nation he visited variously identified as Japan or the Americas.

Etymology

Cynocephalus is a Greek word, literally meaning "dog-head", for a sacred Egyptian baboon with the face of a dog.  

Features

The encyclopedist Vincent of Beauvais acquainted his patron St. Louis IX of France with "an animal with the head of the dog but with all other members of human appearance… Though he behaves like a man… and, when peaceful, he is tender like a man, when furious, he becomes cruel and retaliates on humankind" (Speculum naturale, 31:126). 

Famous

St. Christopher was believed to be a giant of a cynocephalic species in the land of the Chananeans (the "canines" of Canaan in the New Testament) who ate human flesh and barked. Eventually, Christopher met the Christ child, regretted his former behavior, and received baptism. He, too, was rewarded with a human appearance, whereupon he devoted his life to Christian service and became an athlete of God, one of the soldier-saints In the Eastern Orthodox Church, which has not downgraded Saint Christopher, certain icons covertly identify him with the head of a dog.