I think it’s good practice as a DM to let players gain the magic items used against them, as opposed, as we see often in published modules, to inventing contrived reasons to keep it away from them. The PCs killed a Goblin Boss spider-rider last session who wore this weird hat, so here it is.
Hat of the Spider
Wondrous item, rare (requires attunement)
While wearing this hat, you gain the following benefits:
- You ignore movement restrictions caused by webbing.
- You have the ability to comprehend and verbally communicate with spiders.
- You can use an action to conjure a Swarm of Spiders (Monster manual: Swarm of Insects statistics) within 90′ of you that will be under your control for 10 minutes and then disappears. Once used, this property of the hat can’t be used again until next dawn.