I imagine it somewhat like the birth of the Jersey Devil. >>The legend states that Mother Leeds had 12 children and, after finding she was pregnant for the 13th time, cursed the child in frustration, crying that the child would be the devil. In 1735, Mother Leeds was in labor on a stormy night while her friends gathered around her. Born as a normal child, the thirteenth child changed to a creature with hooves, a goat's head, bat wings, and a forked tail. Growling and screaming, it beat everyone with its tail before flying up the chimney and heading into the pines.