There is no excuse for any of this.

Notes:

Completely different vibe right off the bat. The coeurls are a salient species who formerly had an industrial civilization, but it collapsed because their population outpaced the amount of “id-creatures” to feed on.

The tentacles function as hands.

Apparently they’re immortal so long as they have a continuous supply of id— the viewpoint coeurl (who does not have a personal name and refers to both himself and his species as “Coeurl”) personally remembers the civilizational collapse.

Human spaceship shows up, they correctly surmise that the coeurl they meet is the same species who built the ruins around them despite having incompatible communication methods. Meanwhile the coeurl immediately recognizes the spaceship for what it is and plans to hijack it.

Hm. No displacement so far, but the coeurl moves very quickly and stealthily at least: “He floated along in great gliding leaps, a shadow among the shadows of the rocks.”

Apparently id is stored in the bones. At least for humans. Coeurl notes this when he ambushes and kills one, which probably indicates that it’s not the case for all species.

“Kent and Jarvey had chummed together for years in the way only two men can.” Not sure how to interpret that one in 1939.

Oh hey, another illustration. The scene it’s depicting hasn’t come up yet though.

Lots of talk about patterns of cultural development that seem suspect to me but that I don’t know enough to interrogate properly.

“I say that this culture ended abruptly in its most flourishing age. The sociological effects of such a catastrophe would be a sudden vanishing of morals, a reversion to almost bestial criminality, unleavened by any sense of ideal, a callous indifference to death. If this… this pussy is a descendant of such a race, then he will be a cunning creature, a thief in the night, a cold-blooded murderer, who would cut his own throat for gain.”

The above is deduced from architecture that he’s been looking at for like a day. Ridiculous chain of reasoning. He doesn’t deserve to be right about that. Hope he gets his id eaten.

Yep, all the phosphorus has been extracted from the dead guy. The humans suspect the coeurl because like. There’s nothing else around that looks dangerous. They offer him a bowl of phosphorus to see what happens.

And the coeurl describes the phosphorus in the bowl as having id-vibrations, so it’s not just that removing someone’s phosphorus removes their id; apparently the two are one and the same even if the phosphorus is just like. Loose.

Okay, so what the coeurl can do is mess with “vibrations”, which is a pretty broad category. He shrugs off a “vibration gun” one of the humans fires at him after he throws that bowl of phosphorus — that’s what’s in the illustration, him dramatically rejecting the phosphorus to allay suspicion — and then is apparently able to screw with the… X-ray? the biologists on the crew want to take of him.

There’s a debate among the humans re: whether they should kill him under suspicion of eating that guy, but they’re not really sure it’s him, and scientific curiosity makes most of the crew want him alive.

They lock him up, but apparently the vibration thing also lets him manipulate electronic locks.

“The monster merely used his special powers to interfere with the electronic tensions holding the metal together. That would account, too, for the drain on the telefluor power cable that Pennons noticed. The thing user the power with his body as a transforming medium…

Another illustration, once more placed earlier in the story than the scene it depicts for some reason:

The vibration thing also means the coeurl has an almost supernatural awareness of its surroundings.

Apparently the vibration thing also allows the coeurl to make metal stronger.

Whole story is very 1930s, including uncomfortable background assumptions.

That nonsense anthropologist does not get his id eaten like I thought he deserved, and instead gets the last word in the story. At which point the narrator is vaguely racist about his Japanese ancestry, so now I'm offended on his behalf in addition to wanting him to get eaten by a monster, which mostly just makes me annoyed with Van Vogt.

All right, so here’s what I figure. The coeurl’s ability to manipulate vibrations is clearly designed to make him a threat in a science-fiction setting because it lets him screw with the technology the protagonists rely on. A straight-across conversion to a fantasy setting just wouldn’t express the same kind of thematic unity.

As comparison, here's the entry for the Displacer Beast in its first appearance, the 1975 Greyhawk supplement:

A Displacer Beast somewhat resembles a puma, although it has six legs and two tentacles grow from its shoulders. It color is blackish, and its eyes glow a hellish green. They always appear to be 3' from their actual position, so for purposes of hitting them, or when they must make saving throws, they are treated as a man wearing a displacer cloak as far as penalties and bonuses are concerned. Their magical resistance is high, equalling that of a 12th level fighter. Its primary weapons of attack are the two tentacles which are armed with rough, horney edges which inflict horrible wounds. There is great enmity between Displacer Beasts and Blink Dogs.

It looks to me like the idea is that the ability to control waves of light, allowing the displacer beast to appear to be a few feet away from where it really is, was considered a similar concept that would be more easily expressible in a fantasy game. The magic resistance is probably the equivalent of the coeurl's ability to shrug off ray guns and electric shocks. So that all makes sense.

The fact that "id" and "phosphorus" are apparently the same thing does not make sense and is not explained, which is probably why that particular business did not make its way into D&D. I have some questions for Mr. Van Vogt about that, but it seems he's been dead for more than 20 years, so I expect an explanation is not forthcoming. However, if I had to try and make sense of it myself, I'd say something like this:

It is not the case that the Freudian id is, in fact, made of phosphorus. Since getting one's id eaten in this story is apparently universally fatal, we can't make any claim regarding the psychological effects of having it removed. If someone survived having their id eaten, and then was walking around acting in a manner than indicated they were all ego and superego (yes I know that's not how psychology works, but I don't think Van Vogt did), then the phosphorus thing would be a conundrum. However, since that does not happen, we can make the argument that the references to "id" are not intended to be the psychological id of the victim, but that of the coeurl: id-vibrations and id-creatures are so called because they provoke the coeurl's id as a predator. It is just eating phosphorus, but one of the recurrent motifs of the coeurl's internal psychology is that its predatory instincts sometimes overwhelm its more rational thoughts. It thinks of phosphorus as "id" because it triggers these instincts, not because it's literally the id of the prey.