While most people think about spiders being solitary hunters and warriors, there are some spiders que are very communal. They work together, hunt much larger food together, and spin massive webs that hold over 50,000 spiders. While you might not pit the party against that many giant spiders, it might be interesting to walk into a forest that has been taken over by a massive horde of spiders. Swarms, regular spiders, and giant spiders can all live together as part of a community inside an overgrown forest or jungle. That can certainly be a scary environment to be in for any arachnophobes in the group, especially since just about everything is covered in webbing… and we all know about the spider's web sense! Additionally, you can treat spiders as a hive minded race, and perhaps they are intelligent. That's certainly an adventurer hook that will carry a campaign! Which does lead to the next question.