What Makes a Good Monster?

The Psychology and Philosophy of Horror

By Dr Neel Burton — Psychiatrist, philosopher, and wine writer; Fellow of Green Templeton College, University of Oxford; author of over twenty books.

Essay substantially revised on 9 September 2026.

According to Forbes, horror movies rake in around a billion dollars a year. The meat of horror [Latin, ‘a trembling, a shaking’] is, of course, the monster [Latin, ‘bad omen’], whether the great white shark in Jaws or the White Walkers in Game of Thrones, or, in Greek myth, the Gorgon Medusa, the sea-monster Cetus, or the Minotaur.

So, what makes for a good monster?

An effective monster is not only terrifying, like a roaring lion or stampeding elephant might be, but also revolting. Adapting the insights on ritual impurity of the anthropologist Mary Douglas (d. 2007), the philosopher Noël Carroll argued that a good monster displays one or more of four sometimes overlapping forms of impurity:

1. Categorical interstitiality is when something is more than one thing. Greek myth is full of interstitial monsters such as the chimera (part lion, part goat, part snake), the griffin (part lion, part eagle), and the harpy (part bird, part human).

2. Categorical contradictoriness is when something violates binary classes of existence, in particular, something that is both dead and alive, like Frankenstein’s monster or Count Dracula, or something that is both animate and inanimate, like a haunted house or even, at a stretch, the Temple of Doom in Indiana Jones with all its elaborate booby traps. The ability to distinguish between animate and inanimate is acquired at just six months of age, and is so basic as to be built into language. For example, although this usually goes unnoticed even by native speakers, English restricts the use of the present perfect tense (‘has been’, ‘has seen’…) to subjects who are still alive, marking a sharp grammatical divide between the living and the dead. A dead person cannot ‘have been’ or ‘have seen’ anything.

3. Incompleteness is when something is missing a part or parts, like an eye or limbs, or even an entire body in the case of the cannibalistic Flying Head of the Iroquois Indians. In antiquity and later, people believed distant lands to be inhabited by headless men called akephaloi with their facial features in their chest, and monopods with a single leg ending in a gigantic foot. To incompleteness, I would add ‘overcompleteness’, like Cerberus, the three-headed Hound of Hell, or sharks with their several rows of triangular teeth.

4. Formlessness is when something lacks clear boundaries, and therefore, as with interstitiality and contradictoriness, eludes categorization. Examples include werewolves, Dr Jeykll/Mr Hyde, the Blob, the Nothing, and the Fog.

Carroll added that, for extra horrific effect, a monster may be magnified or massified, that is, made larger in size like Fenrir, King Kong, or Godzilla, or multiplied in number like the army of the dead in Lord of the Rings.

Many monsters also have a trait that Sigmund Freud called ‘the uncanny’. In 1970, the professor of robotics Masahiro Mori posited the theory of the uncanny valley. He observed that, for the most part, our emotional response towards machines is fairly neutral, while our emotional response towards human beings and objects such as teddy bears is fairly positive. But if an entity looks almost but not quite human, it arouses negative feelings of eeriness and revulsion.

How to account for the uncanny valley? It could be that humanoids such as the Joker, or cyclops or satyrs, evoke death or illness. Or that they ‘mess with the mind’ in some way—perhaps by violating norms and expectations, or by being deceptive or difficult to read. The Joker wears a flower that can squirt deadly venom: that a flower is normally harmless, even delightful, underscores his deeply deceptive nature.

What is the function, and the appeal, of horror, both in myth and elsewhere? On one level, horror excites our curiosity and imagination, notably through the violation of norms and expectations, the exploration of taboos, and the creation of dramatic suspense. On another level, it gives us licence to unleash our darker side, that is, our Freudian id or Jungian shadow. Shapeshifters such as werewolves and Dr Jekyll/Mr Hyde are commonly interpreted, in their different aspects, as the psychic layers of one, same person. Other monsters, often supervillains such as the Joker, are so overrun by their shadow as to be nothing but darkness.

But the main attraction of horror is, of course, the fear to which it gives rise. Both fear and disgust are among the six basic emotions proposed by the psychologist Paul Ekman—the other four being happiness, sadness, anger, and surprise. Basic emotions evolved in response to the ecological challenges faced by our remote ancestors and are so primal as to be ‘hardwired’, with each basic emotion corresponding to a more or less distinct and dedicated neurological circuit.

Still today, specific phobias are generally for the natural dangers that commonly threatened our ancestors, such as spiders (arachnophobia), snakes (ophidiophobia), and blood (haematophobia), even though in the modern world man-made hazards such as guns, cars, and electric cables are far more likely to strike us down. For most of our evolutionary history, our greatest fear was to fall prey to a predator, to become someone else’s dinner, someone else’s meat.

Horror reawakens that primal fear of falling prey to a predator, and this can serve a number of functions.

First, it can help us rehearse for danger, like children do when they chase one another and pierce our ears with their screams.

Second, it can help us confront and process past experiences by, in some sense, replaying or reawakening them.

Third, and most important, it can give us pleasure, if not perhaps in itself, then at least in the release and relief that follow after it.

When I visited the remote Cederberg winery in South Africa, more than 20 miles down a gravel track off the Cape-Namibia Route, I was handed the key to a nearby cave complex containing prehistoric Bushmen paintings, which I proceeded to explore on my own, without so much as a telephone signal. I still remember the intense ‘joy-safety’ that I experienced upon returning to my Jeep and shutting the door on all the venomous vipers and spiders that had been closing in on my imagination.

Also worth noting is that intense negative emotions can become pleasant if their object or conditions are a simulacrum, which is why people turn not only to horror but also to things like rollercoasters and sadomasochism—which, when poorly executed, can, like horror, quickly descend into farce.

In myth especially, the monster may variously represent: our fears, death, nature, our parents, society, our ego, our id or shadow, our former self, our body, greed, lust, envy, and/or a threat to humanity.

The monster is, in short, everything that petrifies us—quite literally in the case of the Gorgon Medusa.

And it is the thing that every hero must slay.