Halloween is still a few weeks out here, but it is the season, after all, so let's check out this question that came into our box: With the Month of Fright upon us, what can you tell us about all the dead monsters that go bump in the night? Or the day, as the myth may be.
That's a topic that is enormous: the idea of the dead troubling the living, and creatures that are dead, though they were once alive, menacing the world in the dark and light alike. Most cultures have ideas about how the dead and the living interact and how the one might endanger the other, and along with that very often comes the fear of the power the dead might wield over the living if they intrude into the domain from which they should now be barred.
For many cultures (and of course their folklore), the problem of the dead or the undead endangering the living is fundamentally one of the rightness and wrongness of the universe. The dead aren't evil, of course - even in cultures that don't practice ancestor worship, wherein the dead are venerated and beloved as lost family members and wise elders, the dead are generally not malevolent in and of themselves. They pass away into the underworlds or the spirit realms or are reincarnated as new living beings or simply become one with the universe again, depending on the mythology in question, and this is a cause for grief for those they leave behind but not inherent fear or dread. The problem is when the dead end up where they aren't supposed to be - among the living, who may be hurt by their presence or actions, or even just edged out by the dead taking up space and resources that they are no longer entitled to. The idea that the dead might want to keep the things they had in life and therefore deprive or displace the living is one of the oldest and most basic fears in folklore and religion; after all, you can handle other living things, but over the dead, no one living has much power and there is no hope if they decide to interfere or assault the living.
Ghosts - incorporeal spirits of once-living people - are a staple of human belief about the dead, but they don't always take the same form across different cultures. Personified spiits that appear the same way they did in life have appeared in art for millennia, with the Egyptian paintings of the spirits of deceased pharaohs traveling to the underworld and encountering their gods among the first. Of course, the pharaonic spirits are going to the afterlife the way they're supposed to, so there is no fear associated with them; but ghosts who are in the world of the living are threats or at least unnatural problems to the safety and peace of humanity. For most peoples, funeral rites were designed not just to allow the living to say goodbye to their loved ones, but to give the dead peace (or, if necessary, ironclad restriction) to prevent them from hanging around and causing problems.
Every culture, even the ones big on ancestor worship, is usually afraid of ghosts that linger in the world. Japanese folklore about yurei tells tales of ghosts that murder, devour or mislead human beings to their deaths, often as revenge for what was done to them when they were alive or hatred that was instilled in them when they lost their lives. The ancient Mesopotamians believed in the gidim, shades of the dead who did not go to their final disposition in the underworld as they should have and instead became minor demons of the land of the dead, capable of harasing, sickening or even killing the living if they were not properly respected. Greek and later Roman ghosts seldom endangered people, but instead terrified and inconvenienced them, haunting the living with loud cries, frightening visions and disordered houses until they were appeased, usually by being given proper burial rites that had been neglected. The Dine people of the southwestern United States tell stories of chindi, ghosts who torture the living with sickness and death when they are doomed to remain on earth because they did not receive funeral rites as they should have, taking the living with them. And so on and so forth: when the dead remain in the world, there is no peace for the living.
Ghosts are only the beginning, though; humanity is incredibly creative when it comes to speculating about various types of dead creatures that might get up and come after them. Corpses are innately psychologically horrible to the vast majority of humanity; they look like living things but aren't anymore, reminding us that we, too, could suddenly stop being alive at any time, and the terrible things that happen to them, from putrefaction to dessication to the buildup of gases and discoloration of decay only enhance and heighten that horror. Ancient people also didn't always have a great deal of medical knowledge, so things like bloating, changes in skin color or hair growth in the dead sometimes seemed inexplicable and frightening, sure signs that they weren't truly dead after all.
One of the most popular versions of this idea is the vampire, a folkloric phenomenon that can be found, in one form or another, all over the world. Not all vampires are necessarily dead, actually; the earliest form of the Greek vrykoulakas, for example, was not a dead person drinking blood but a living monster or sorcerer that did so. Other forms of vampires, like the Romani mulo or Chinese jiangshi, are definitely dead, however, and their drinking of living blood is an extension of the mythological belief in some cultures that life is contained in blood. If enough of a person's blood is spilled, they die, so for many pre-medical-knowledge folkloric beliefs, it only made sense to view blood itself as being what contained the force of life. (And for the record, for the same reason some ancient peoples, including the Greeks, believed that ghosts were composed of breath, another thing that the living abruptly die when they are emptied of it.)
You asked about things that go bump in the night or day, and vampires are a perfect example. Although modern folklore makes vampires only active at night, even going so far as to say that sunlight is painful or even fatal to them, more ancient folkloric vampires were capable of appearing in the daytime at will than not, including the barrow-haunting draug of Icelandic myth and the daywalking strigoi of Romanian legend. Fear of sunlight didn't appear as a major element of vampire folklore until the nineteenth and twentieth centuries, if you can believe it - even Bram Stoker's Dracula doesn't care about sunlight particularly except that he's more powerful at night which is his element.
Vampires are a whole other realm of discussion, since creatures that feed on humanity by in some way stealing from them goes well beyond blood, including such creatures as the Middle Eastern edimmu who feed on the spirits of lost mortals in the deserts and the pishtaco of Peru who suck not blood but fat from their victims. But most of these kinds of creatures aren't actually dead, and don't quite fit into the Halloween theme, so let's move on!
I want to hit a couple of common undead tropes in modern fiction and folklore that actually aren't dead things that go bump in the night, because I'm in a fun The More You Know mood and I love talking about them! Those two things are the ghoul and the zombie - both with very real roots in very real folklore, but neither one actually dead, undead, or in one case ever human to begin with.
The pop culture idea of the ghoul comes from Arab folklore, where you can find the ghul, a desert spirit that aggravates, frightens and even occasionally hurts human beings when it wanders into their environs. Ghilan (the plural form of ghul) are not dead, and in fact are similar to the jinn, spirits of invisible flame, than to any undead creature; they live out in the deserts, almost all appear in female form, and harass travelers and nomads by impersonating humans to steal or befoul food, frighten or mislead caravans, or occasionally steal children (although what they do with them is anyone's guess, since most tales just say they ran off with the kid and don't mention whether or not they actually hurt them; occasionally, they're said to eat them). They're certainly unpleasant and can be very dangerous, especially if pissed off enough to lead a lost person out to die in the desert or bewitch one person into attacking another, but they pretty much have nothing to do with the dead.
The connection to the dead for ghilan largely comes from 1001 Nights, which was first made pouplar in Europe through the French translation of Antoine Galland, who in spite of translating the majority of the stories faithfully also added several embellishments of his own. In particular, he added during the description of ghilan in one story that they were monsters that sometimes went to graveyards and ate dead bodies when they couldn't get living prey, along with characterizing them as uniformly male. This didn't appear in the original stories he was supposed to be transcribing (obviously, since calling the all-female ghilan all-male was a pretty big giveaway) and was a personal addition he made to sensationalize the story further, but since his was the first popular translation, it was the one that most people encountered; and then other translators used it as the basis for their versions, not the original, so the addition was repeated and circulated into English, German, Spanish and more. Scholars who wrote about mythology and folklore who didn't speak Arabic but wanted to learn and talk about Arab myths also used those translations, so the idea of the ghul as an eater of corpses persisted, and eventually became synonymous with the idea of the ghoul as a reanimated corpse itself.
The confusion was further entrenched later when western scholars equated the ghilan with the gallu, ancient Mesopotamian underworld demons that do the bidding of the gods of the dead. The words are etymologically similar, and it was (and still is) very in vogue to trace all Middle Eastern myths back to Akkadian/Babylonian roots and claim that they were essentially the same, so the ghilan became considered the same as the gallu, and the gallu are strongly associated with death. So ghouls became firmly entrenched in popular culture as a new breed of the undead, light years away from the original Arab folklore roots of the idea.
Zombies are a little more complicated, because they belong to folklore and religion that are very much alive and influential in the Caribbean, but in its original form, a zombi (from the Kongo nzanbi, meaning "soul") referred to a living person who had been mind-controlled by a bokor or sorcerer, a common phenomenon in areas where west African folklore has been transplanted to the Americas, particularly Haiti. Sorcerers considered to have the magical power to control the minds of those who defied them are able to make the living appear to be dead, and to wipe away their thoughts and free will in order to use them as servants as needed. Over time, it has also become common knowledge that bokor can resurrect the corpses of the dead to use as their servants, sometimes by temporarily placing a soul inside them to animate them, other times only via their own magical might.
It's likely that this idea has its roots in the concept of spirit possession by the orisha and loa of African diaspora religions; the spirits of the gods can and do possess their worshipers in order to make themselves known and grant blessings or curses, and the idea of inhabiting a body (living or dead) with another's will proceeds naturally from that religious concept. Some worshipers connect zombi to Baron Samedi and the other loa of the dead, who like the other loa might choose to possess and ride the bodies of mortals, but whose connections to death make them more suited to do so with the bodies of the dead than the living.
Zombies as seen in horror movies, though, like the ghouls above, are almost completely a modern pop culture invention. The dead rising from their graves and seeking to feed on the living is a general folkloric fear that you can find in a zillion different places and styles, that same idea of the dead intruding on the space of the living being a danger that we started this post with. Modern versions of the idea have posited all kinds of different sources and reasons for zombies, from viruses to evolution to pollution or nuclear fallout, but it's really just a repeat of the idea of the fear of the unquiet dead, now with a collection of brand-new modern mythology behind it.
Which is super neat, when you think about it, really! We're all aware that religion and mythology continue all around the world, alive and fervently believed by their worshipers, meaningful and impactful in billions of lives, but it can be easy to forget that that means that things change and no myths can ever really be set in stone and classified as eternal and inviolable. We're all making new myths all the time, because that's what humanity does, and humanity is pretty amazing.
So, while from a purely folkloric point of view you don't need to fear ghouls if you choose to lurk in a graveyard this Halloween season, there's plenty of precedent for terrifying creatures that lurk in the dead of night. Humanity has feared the dead arising for thousands upon thousands of years... it seems foolhardy to believe that they must all have been wrong all that time, doesn't it?