This list of mythical creatures that begin with this letter and I am constantly gathering information from each continent, and is continually being updated.
Sack Man (Worldwide)
The Sack Man (also called the Bag Man or Man with the Bag/Sack) is a figure similar to the bogeyman, portrayed as a man with a sack on his back who carries naughty children away. Variants of this figure appear all over the world, particularly in Latin countries, such as Spain, Portugal, Italy (where he is known as the vecchio col sacco ("the old man with the sack").
In Spain, el hombre del saco is usually depicted as a mean and impossibly ugly and skinny old man who eats the misbehaving children he collects. The crime of Gádor gave rise to this term because the kidnappers used a gunny sack to carry with the children. In Brazil, is portrayed as a tall adult male, usually in the form of a vagrant, who carries a sack on his back, and collects mean disobedient children for nefarious purposes.