Sack Man

The Sack Man is a bogeyman figure found across many world folklore, particularly prominent in Latin countries such as Spain, Portugal and South America.

The European take on the entity has its roots in two distinct tales, though like most regional bogeyman figures these two "origin" tales are only the most famous and countless regional variants exist.

There are also many other "Sack Man" myths found across the world, as seen here:

https://en.wikipedia.org/wiki/Sack_Man

15th - 16th Century Orphans
The earliest tales of Sack Man (at least in Europe) originate from memories of a practice during the 15th and 16th centuries in which orphaned children (mostly infants) would be abandoned, causing a man to travel the streets by cover of night and collect them in "bags" (or caskets), due to the horrendous lack of care for said infants many died on the trip to local orphanages and over time the myth was born, told as a means to scare children into good behavior.

Gador Murders
https://en.wikipedia.org/wiki/Crime_of_G%C3%A1dor

A much more recent origin of the tale comes from murders in Gádor, a town in Almería, in 1910.

Francisco Ortega el Moruno, was seriously ill with tuberculosis and was desperately looking for a cure. He went to a healer, Agustina Rodríguez, who, upon seeing the case, sent him to Francisco Leona, a barber and healer who had a criminal record.

Leona asked him for three thousand reales in exchange for the cure and revealed the remedy: he had to drink the blood of a healthy child, fresh from the body, and put plasters of the creature's still-hot butter on his chest. He promised her that that way he would heal right away.

Leona offered himself to look for the boy and, after unsuccessfully offering money to several peasants in exchange for his children, he went out together with Agustina's son, Julio Hernández the fool, in search of a lost child.

On the afternoon of June 28, 1910, seven-year-old Bernardo González Parra was kidnapped, who had lost himself while playing with his friends and had separated from them. Leona and Julio put him to sleep with chloroform, put him in a sack and took him to the farmhouse in Ardoz, isolated from the town, which Agustina had made available to the patient. Another son of Agustina, José, went to tell Ortega, while his wife, Elena, was staying in the house, quietly preparing dinner.

Once everyone was in the house, they took Bernardo out of the bag, awake but stunned, and made a cut in his armpit to draw blood, which they collected in a glass. Mixed with sugar, Ortega drank the blood before it got cold. Meanwhile, Julio killed the little boy by hitting his head with a large stone. Leona opened the boy's belly and extracted the fat and the omentum, and wrapped everything in a handkerchief that she put on Ortega's chest. Once the ritual was finished, they hid the body in a place known as Las Pocicas, in a crack in the ground, and covered it with herbs and stones.

When making the distribution of money, Leona tried to deceive Julio and did not pay him the fifty pesetas that he was promised for the murder. He decided to take revenge and told the Civil Guard that he had found the body of a child by chance while he was hunting hares. They arrested Leona for having a criminal record, and she blamed Julio, who initially claimed to have witnessed the crime from some bushes. In the end the two men confessed to the crime.

The Civil Guard detained all the people involved in Bernardo's murder. Leona was condemned to the vile club, but died in prison. Ortega and Agustina were also sentenced to the maximum penalty and executed. José was sentenced to 17 years in prison and his wife, Elena, was acquitted. Julio the fool, damned.

Similar Monsters

 * Coco
 * Boogeyman
 * Uncle Sain