This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Herensuge (Basque)
Herensuge is the name for a mythical dragon in the Basque language. In Basque mythology, dragons appear sparingly, sometimes with seven heads. Herensuge often also appear in the form of a serpent. The seven heads were believed to be the offspring of the Herensuge dragon. When the little dragons were fully grown, they would fall off their mother's head. Only the god Sugaar is associated with this creature but more often with a serpent.
In stories in which it lived in the mountain range of Ahuski, the Herensuge used its breath to attract the cattle that grazed in the area and when it lived in Aralar, it fed on human meat. In stories told in Ezpeleta, upon forming its seventh head it bursts into flames and flies swiftly toward the region of Itxasgorrieta "region of the red seas", in the West, where it sinks.