This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Sigbin (Philippine)
The Sigbin or Sigben is a creature in Philippine mythology said to come out at night to suck the blood of victims from their shadows. It is said to walk backwards with its head lowered between its hind legs, and to have the ability to become invisible (have a stealth ability) to other creatures, especially humans.
It resembles a hornless goat, but has very large ears which it can clap like a pair of hands and a long, flexible tail that can be used as a whip. The Sigbin is said to emit a nauseating odor. The myth is popularly known in Visayas Islands and Mindanao especially in rural areas. It is also said that it looks like a dog and owned by rich people who hid those creatures in a jar.