The best way I know to make a setting creepy, uncanny, and also humorous, is to use cults. Cults are a fantastic framing device: They allow us to distil ideologies, emotions, or even personality traits into a single organisation. That is very powerful, for a GM, and a great framing device for the other players to see the setting.
And just like yesterday, I have 3 easy steps to create cults.
Step #1 - Think of something mundane, yet importantE.g. Salmon migrate from the ocean, upstream, to spawn in the upper reaches of rivers.
It's best to think of something that the average person in your setting would notice and would care about. Aspects of the world that have conflict (supposed or real), or that are important phenomena. In the above example, when the salmon come to migrate, they would be much easier to catch, meaning there would be much more food available.
Step #2 - Make a reasonable, but incorrect, leap in logicE.g. Salmon migrate to the rivers because they're running from a monster that wakes up in the oceans, annually.
Here, if there isn't already conflict in the idea, add it. Preferably one with agency behind it. Something does something else to the focus. This leap in logic should attempt to explain the phenomenon in ways that the average lay person could rationalise and agree with... Imagine a cultist attempting to recruit new followers: How would they use this leap in logic to sway new folks into their line of thinking? The more reasonable the leap, the better. But also remember, the more tension and drama in the leap, the more compelling it will be, and the more people will want to believe it.
Also, don't be afraid of making utterly ridiculous leaps in logic - even ones that everyone in the setting has already put to bed. Consider how widely prevalent the Flat Earth Society is in our modern day, and the arguments they make to support their fallacy (and the arguments that their recruiters make to gain more of a following). In fact, the Flat Earth Society is a fantastic example of a modern cult. They're well worth studying for the GM's toolbox (and for a laugh, and perhaps a cry, if you need it).
Step #3 - Make a further leap in logic, based off the first, that leads to an actionable stepE.g. If we eat better when the salmon are upriver, and the salmon go upriver because the ocean monster is awakened every year, we need to keep the monster awake constantly so that the salmon never leave!
Now we've got a cult that parade on the beaches with pots and pans, banging them together to keep the ocean monster awake...
This step is best done when the actionable step is simple enough that any lay folk could do it, without dedicating their entire lives to it. However, it should also have room to grow for some kind of extreme cult... Whilst the cultists convince the lay folk to bang on pots and pans, the upper echelons of the cult are working on a giant whirlpool machine, so that they can cause the ocean to be constantly in rapid motion, to keep the ocean monster awake forever!
You can even run this system several times on the one idea, repeating steps 2 & 3 over and over again, on the same premise. This is a great way to get sects within a cult, or to create conflicting yet equally ridiculous ideas.
This system works well to create anything from dangerous blood cults to silly folk-practices and superstitions.