WARNING: This post contains nothing but SPOILERS.
Please read ALL Laird Barron stories before reporting back here.

Davis swore he had heard chuckling and whispering behind the steel door after curfew.
(“Old Virginia”)

The chuckle is the most menacing form of laughter.

This is because, I believe, a chuckle is a private laugh.

It is a self-congratulatory laugh. It is produced when we recognize the amusing fact that we are the only ones who are in the know. One chuckles to oneself, and often at the expense of others, presumably out of earshot.

It is smug.

An overt chuckle is menacing simply because we are social animals. When we hear it, we naturally infer that we are missing something. If the situation were truly funny, we would be sharing a laugh. Instead, a chuckle implies that we are missing a crucial piece of information which we have either failed to obtain or which has been withheld from us.

It implies that we are the joke.

A person may chuckle in our presence but immediately apologize and let us in on the joke. That is rude but forgivable. It is the person who chuckles openly and unapologetically that causes concern. They are either entirely lacking in self-restraint, or so little threatened by us that concealing their amusement at our expense is unnecessary.

"My men," I said. It was difficult to talk, my throat was rusty and bruised. "With Mother. Except the brute. You killed him. Mother won't take meat unless it's alive. Shame on you, Roger." She chuckled evilly. ("Old Virginia") 

Poor Roger knows to expect the worse from Old Virginia.

A chuckle becomes much more worrisome when we are not sure just who … or what … is doing the chuckling. There are few things as terrifying as a chuckle which floats out of the darkness in which we thought ourselves alone.

"Hey." The voice floated from the thicker shadows of the alley. It was a husky voice, its sex muted by the acoustics of the asphalt and concrete. "Hey, mister." 
 

Wallace dragged on his cigarette and peered into the darkness. The muscles in his neck and shoulders bunched. His hand shook. He opened his mouth to answer that odd, muffled voice and could not speak. His throat was too tight. What did it remind him of? Something bad, something tickling the periphery of his consciousness, a warning. A certain quality of the voice, its inflection and cadence, harkened recollections of hunting for tigers in the high grass in India, of chopping like Pizarro through the Peruvian jungles on the trail of jaguars—of being hunted.  

"Mister." The voice was close now. "I can see you. Please. Prease." The last word emerged in a patently affected accent, a mockery of the Asian dialect. A low, wheezy chuckle accompanied this. "Prease, mistuh. You put a hotel in my rice paddy, mistuh." (Hallucigenia)

What’s most troubling about the chuckle in Laird Barron’s stories is that it is frequently deployed maliciously by the chuckler. Wallace has it right. He is being hunted, and he is being chuckled at because fear changes how he is going to taste. He is being seasoned.

"Mother wants to meet you. Such a vital existence you have pursued! Not often does She entertain provender as seasoned as yourself...”  (“Old Virginia”)

Fear sweat is distinctive, any predator knows that. This pungent musk superseded the powerful cologne and stale odor of whiskey leaching from his pores.  (“Shiva, Open Your Eye”)

Butler chortled from a spider-cocoon in the green limbs, "Now you're seasoned for his palette. Best run, Pinkerton. You've been in the sauce. Chewed up and shat out. And if you live, in twenty years you'll be another walking Mouth." He faded into the woodwork. (“Bulldozer”)

My weakness is the life essence of primates who take a swim in the Great Dark and return, brimming with eldritch vitality. (Xs for Eyes)

(The chortle is a particularly loud chuckle, it should be mentioned.)

The ogres (the shape-shifting, man-eating giants of folklore) in Barron’s stories are apex predators. They hunt humans, and they have very particular tastes. With the benefit of hindsight, we can see the pattern start to emerge in the earliest stories. There is something about the brain which has been through an emotionally taxing experience that lends it a flavour which they find delightful. The more such experiences the better.

(They also eat children, yes, but I suspect that they do so primarily because of its impact on the witnesses and survivors. You can season an entire community with one little bite.)

Now, however, you are in on the joke. While the protagonists sweat, you can withstand any amount of chuckling with equanimity. You may even enjoy a chuckle at their expense.