King Kong's monstrous motivations aren't the same as Dracula's — one wants a castle made of bananas, the other a swimming pool full of hemoglobin — but, on a psychological level, their motivations differ too. Here's Chris Braak's monster taxonomy.
All this talk about evil got me thinking about monsters. I'm going to eventually have to write more about evil - I still don't like it, either as a qualifier or as a story-telling element, but I think this must be a personal preference, and resolution will require substantial introspection. In the meantime, I'm going to take an old theory I worked on in college, dust it off, and pretend like I thought of it just now. It's about monsters, and the different kinds that there are.
This is not, by the way, monsters in real life: Hitler or serial killers or Jeff Holland, or whatever. This is monsters in the arts.
So, let's talk about monsters. For the sake of this discussion, I'm using the following definition for "monster" - ahem:
An autonomous entity, distinguished by a substantially increased willingness and capacity to inflict harm on the protagonist(s).
I think that covers about everything. From this perspective, I can see basically three different kinds of monsters. The first is the Id-Monster - this is an entity that, by virtue of its will to fulfill its most basic desires, must necessarily cause harm to the protagonist(s). The xenomorph is an Id-Monster. The bear in any movie about someone being chased by a bear. Moby-Dick is an Id-Monster.
Monsters like this are the kinds of things that we usually forgive by saying, "it's just doing what comes naturally to it," which may be true, but obviously has certain built-in limits. Yes, the xenomorph slaughtering the shit out of everything it sees is just doing what comes naturally to it; that doesn't mean you shouldn't kill it. The hallmark of the Id-Monster is usually that it isn't conscious of the harm that it's inflicting - it's either coincidentally unaware, or else just lacks the machinery capable of recognizing that what it's doing is harmful, or even of the concept of harm.
This is distinguished from the second grade of monster, what I'll call (for the sake of consistency) the Ego-Monster. This is an entity capable of recognizing the concept of harm, recognizing that it is inflicting harm, but has no particular interest in avoiding it. In a way, it's impossible to recognize the Ego-Monster as being anything but explicitly sadist, because the Ego-Monster has no purpose except itself; it serves its vanity, and commits harm to do so, because committing harm serves that vanity.
For the Ego-Monster to commit harm, harm must be the intended end, because the Ego-monster does not commit acts except those that are, or lead directly to, intended ends.
Hannibal Lecter is kind of a good example of the Ego-Monster; he behave according entire to his own inscrutable personal laws that have little reference to ordinary social mores and are do not evaluate "harm" as being undesirable. It's what the doctor means when they describe him as being "pure sociopath" - he's not an animal, that doesn't understand that he's harming something. He is a madman that literally doesn't care.
The third kind of monster I'll call the Superego-Monster. The Superego-Monster imagines that it serves a higher purpose, and that the harm it inflicts is to the good. This is the kind of monster that can recognize harm as being undesirable, distasteful, even troubling to his conscience, but he chooses to do it anyway, because of what he is driven towards. This goal is necessarily not concomitant with the human social good (or the protagonist's social good) - the discrepancy between this driving goal and the present good that is its result is a rough analogue for how monstrous we conceive the character to be.
This one's a little rarer and trickier to find an example of; I settled on using the guy from Se7en. He actually believes that he is doing a kind of good - that his murders, beyond simply being the gratification of his own perverted psyche, will improve the world.
Obviously, there are a lot of borderline characters. Is it right to call a serial killer an Id Monster, or an Ego Monster? The serial killer is fulfilling what are, in a sense, deeply-coded functions; base desires that he may not even consciously understand. Likewise, depending on the nature of his psychosis, he may not even be capable of recognizing other human beings as human beings at all. Is this a product of an adapted narcissistic egoism? Or simply an undeveloped consciousness?
Michael Myers is a serial killer; I wouldn't call him an Ego-Monster.
Hitler was a raging Ego-Monster - but his sense of self was so forceful that it became the purpose of innumerable Nazis that worked for him, and thus became Superego-Monsters.
In this light, something like Moby-Dick is kind of fascinating to me. Melville has set up Ahab, clearly a kind of Ego-Monster, up against an Id-Monster - the former is so deeply self-obsessed that he doesn't care if he kills everyone around him to get what he wants; the latter represents the most unconscionable affront imaginable to a rampant egoist - a monster that refuses to acknowledge him.