Might be another mod conflict, but NullPointerExceptions usually aren't hard to fix.
https://pastebin.com/1spKz992

I wish it was that easy; but this appears to be a vanilla method. Somehow something becomes null that the vanilla method does not check for. This could be either another mod or mine but your guess is as good as mine... did it happen randomly or did you see what the baby spider was doing?

Sorry if I sounded a little brash. Unfortunately, I wasn't able to get a glimpse at what the spider was doing, but the crash happened during a Bloodmoon from the respective mod if that helps at all.