it seems to work fine, but it is way to ups heavy, even without any spiders spawning.
medium to late game, I was 60UPS constantly, by just adding the mod it drops to 50.

Would need more time to cook and have some performance upgrades, seems quite nice though.!

Weird, I ran some tests today using the released code, setting tickrate high and got about:

3700 ups on a new save, vanilla
3300 ups on a new save, mod enabled with no spiders
700 ups on a new save, 80 spiders

178 ups on a 250h megabase, vanilla
176 ups on a 250h megabase, mod enabled with no spiders
90-130 ups depending on location on a 250h megabase, 80 spiders

So there shouldn't be a significant slowdown when just adding the mod. However calculating movement of each individual spider every 60 ticks has a performance impact and the limit of spider spawns can be configured in settings. I will improve the spider scripts soon.

well, if you want a sample of the save I'm running right now, just add it to it.
Using the debug window, most mods are at 0.00xxx, but the giant spider was sitting at 0.3 in usage.

It is somehow crowded with other mods for sure, but that will be most people reality, I guess. Maybe something isn't playing nice with each other.
https://drive.google.com/file/d/1cOq7-Iw757iysobFdhbJxTO8Qu1Ywj8Q/view?usp=sharing

lol, of course it won't happen now that I shared hahahha. So I added it back to get the ups part, but now it is not happening, guess I'll need to do some cleanup to have new spawner, I'll post back with some updates.

Okay I think I got it. I got your save to run about 210-280 ups with 80 spiders. One slowdown stems from spiders getting stuck near water and repathing constantly. That dropped me down to even 30 ups. I need to do something about water. There might be other reasons, but likely fixing this will solve the issue.

Here, just enable cheat mode and start killing stuff and generate more chunks will make it clear enough.
https://freeimage.host/i/JhCkVqJ

Great, thanks for looking into it

It seems water sutff was the issue with the ups, thanks