This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Babi Ngepet (Indonesia)
Babi ngepet is boar demon in Indonesian mythology. Babi ngepet are commonly known in Java and Bali. According to local myth, the creature is believed to be the manifestation of a person practising pesugihan babi black magic. Pesugihan is derived from the Javanese word sugih meaning "rich". It is a kind of magic to help people become rich instantly, but in exchange they must sacrifice something.
In this case they must sacrifice their humanity; allowing themselves to be transformed into a boar for a period of time, or allowing themselves to be possessed by a boar demon. The human-animal transformation is similar to shapeshifting or the werewolf concept in the West. Some of the myths told about a man enveloped in black robes before miraculously turning into this creature.