Here's a bit of nightmare fuel for you.
In south Asia, it is said that the there is a creature that may be created by a sorcerer, witch doctor, or shaman out of a dead human fetus or stillborn child. The creatures are said to look like green-skinned, red-eyed goblins, and are controlled by individuals who have created or purchased them. Although their description is often described, they are said to often be invisible without the aid of magic, and some stories seem to suggest that the toyol never leaves it's home, but rather projects itself as a spirit to commit whatever acts may be required of it.
Stories regarding these creatures are spread throughout Asia, and the remains to be used vary - some hold that a stillborn child will do, others than an aborted fetus is best, and others seem to state that any deceased human child will work.The remains are re-animated using magical embalming techniques, and it becomes a servant of the magician that created it, or may be sold to another if the magician decides to do so. Toyols are kept in jars (filled with oil from a human corpse, known appropriately as corpse oil) when not needed, and are brought out when desired by their masters. The toyols are controlled by chants that provide instruction, as well as discipline should the toyol obey. However, the toyol becomes more powerful every year, and can become dangerous to its owner.
The creature is in many ways child-like, needing clothing, food (usually sweet foods, but in some traditions, blood from the mistress of the house though some versions that that they will breastfeed but take blood instead of milk), and toys, and must be cared for. In return, the creature will serve its master, committing acts of theft, sabotage, murder (usually using it's shard claws or reaching through the chest to stop the victim's heart by squeezing it) and other crimes as needed. Male toyols are preferred, as they are more docile and can be easily controlled. Female toyols are more vicious and bloodthirsty. The female toyols tend to be closer to their owners, and often are more possessive of their owners, but (in accordance with the social traditions of the place where these stories originate) will not leave the home and are used more like particularly horrifying guard dogs than the supernatural petty criminals that the male toyols are said to be. Female toyols are also said to be more demanding of their owners, and to make demands that cannot be negotiated with, the way that they can with male toyols.
As noted above, in many versions of the legend, toyols are kept in jars, and in some there is a written contract with the spirit animating the toyol. In these stories, breakign the jar may free the toyol from its obligations, and allow it to attack and possibly kill it's owner. What happens with the contracts is not clear, with some stories sayign that the contracts have end-dates and that after that the toyol may be laid to rest, while others hold that there is no end, with the toyol becoming both a servant and a curse to the owner and to all of their descendants (so, the family curse isn't just for European families in creepy 17th century mansions).
In some versions of the story, a master-less toyol may just wander into the wilds, and go where it can occasionally interact harmlessly with human homes. In these versions to he tales, the toyol can be a heart-breakingly sympathetic character, essentially a lost eternal child that knows it cannot be part of any family, but will seek them out in order to observe longingly, and sometimes sneak into the house to play with toys. However, toyols don't like to be abandoned, and many stories hold that, if they learn that they are to be abandoned or destroyed, they will kill their master and themselves at the same time (worth noting - toyols are intensely jealous, and may take poorly to their master having a child of their own). Toyols who have committed crimes will often fear death, as they will have to go through judgement before being reincarnated, and they will likely be reborn as a lower life form to make up for their sins before being able to work their way back to human.
Though generally used for petty crimes, the toyol could be made more powerful through special rituals and could be used to commit more serious crimes, such as murder, or to bring the owner extraordinarily wealth. In addition to rituals, other ways to increase a toyols power include setting a toyol to suck blood from the toe of a sleeping bride on her wedding night (the bride is usually said to be a relative of the toyol's owner), or having the toyol take control of the owner and eat raw meat.
Luckily for the virtuous among us, defenses against toyols are well known. Placing valuables above needles will keep them from being stolen, and toyols fear being hurt by needles. Placing valuables next to mirrors will also keep them safe, as toyols are afraid of their own reflection. Fianlly, placing sand, strands of garlic, marble, and the like in various parts of the house will distract a toyol, who will spend time playing with them until it forgets its task.
Although generally said to be used for crimes, petty or otherwise, the toyols can also be made to commit other heinous acts, including seeking out spirits of wandering children to be made into other toyols; gathering information (for committing crimes, or for military intelligence); looking into human bodies to identify illness or injury; and foretelling the future.
Commentary: This is more folklore than the typical ghost story that I bring you, but it is so disturbing, weird, and just plain odd that I had to share. Most of what would normally be in the commentary is in the main text above, due to this being a piece of folklore rather than a reported haunting. Nonetheless, there are a few elements of the story that bear further exploration.
First off, though this creature is Asian in origin, and likely not related to European folklore, there are parallels with the
homonculus of European folklore and magical traditions - primarily that a sorcerer or alchemist could use magic to create a small humanoid servant for it's own purposes. That said, many aspects of this story - specifically the use of an aborted or stillborn fetus to create the creature - are specific to Asia, though I do wonder if this story hasn't made the rounds of some of the more rightward churches in the US and Europe, as it seems almost custom-made for linking abortion with black magic/Satanism.
The Atlantic article linked below states that a likely origin for these creature is in pre-Islamic mecca, where infanticide (including burying infants alive) was not uncommon (though, it should be said, this was not uncommon in many parts of the world, including Europe). The story would then, presumably, have spread with the expansion of Islam, likely especially as it was spread through the Moghul Empire. That said, as noted, infanticide is a common practice in cultures throughout the world, and creatures similar in some respect to the toyol are also found in mythologies across the world so while that is a possible origin, it is not the only likely one.
As noted, while the toyol as described above seems to be endemic to Malaysia and Indonesia, variations on the story are common throughout Asia. Versions are reported from China, Singapore, the Koreas, Thailand, Cambodia, and the Philippines, and I would be surprised if versions were not also present in Pakistan, Bangladesh, and Japan, given the geographic spread of these stories. One version of the story even holds that Buddhist monks may carve stone bodies for the spirits of deceased children who are otherwise stuck on earth, though it sounds from my limited reading as if these creatures are more like normal children and are not thought to be evil, but rather are the result of a kind deed done by the monk.
Given that variations of the story are found over a wide geographic range, there is no surprise that the stories appear highly variable, and often scaled to the scope of the people in a region. In small villages, the toyol is said to be the tool of the petty local witch or magician, and commits minor nuisance crimes. In more prosperous areas, the power of the toyol is said to be greater, and their capacity to enrich or harm are more extreme. This seems to make sense, as it is likely that common folklore will scale to the surroundings.