>>28702851Not sure if spooky, but I have some experiences.
I have a Secret Base out in the desert of Hoenn Route 111. It's pretty quiet, sandstorm notwithstanding, but at night all bets are off. The temperature drops down to near-freezing, and Pokemon come out to hunt and to do whatever it is they can't do during the day when it's too hot.
Sometimes the sandstorm in the desert will die down during the night, and you can really get a good look at the landscape, especially if you're lucky enough to see it happen when the moon's waxing. I happened to be in the right place at the right time to see that firsthand, and while the desert really is beautiful, it's also full of some genuinely unsettling sights.
On that night when the sandstorm died down, I decided to go out and look for rare Pokemon and fossils. I knew how dangerous the desert was at night, but I decided to go out anyway like an idiot, and nearly lost my foot in a damn Trapinch nest.
Go far enough back into the valley though, and you'll run into this massive rock, just kind of standing off by itself. It's eerily silent around that thing, and I've never seen even a Sanshrew go near it. People talk about how the desert is a lifeless dead-zone, but it really WAS completely dead around that rock. Not even a straggling plant, just sand, stone, and silence. The rock itself had some weird markings on it, but I couldn't make out anything specific -- probably eroded from the elements. It's unsettling to go near.
The real danger at night is honestly Cacturne. They will follow you in packs, just like their 'dex entry says. What it doesn't say is that they will flank you and try to cut off your exit if they can -- if I hadn't had my Pokemon with me, I don't know what would have happened, because that night they followed me all the way out of the desert (I wasn't about to lead them to my Base.) I still see them looking at me sometimes when I'm out there, watching and waiting. They'll wait forever.