Are you scared of spiders? For if not, you probably will be after visiting this little gem in the Suzerain Scrying series of resources.
Adventurers are faced with a narrow passage, a lot of webs around... place virtually undisturbed save the recently-deceased corpse of an earlier (and unluckier?) adventurer lying in the far corner. The good news is that the spiders visible are regular-sized, not the giant man-eating sort all too often found down a dungeon. Going in?
As well as an atmospheric description, replete with details just waiting for the observant to notice, there is a beautifully-clear explanation of how the webs actually work, how they are used by the resident spiders to their advantage.
The accompanying rules section gives all the details you need, and even if you don't happen to be using the Suzerain ruleset there is enough information that should you like the idea of this dungeon room, it will translate readily to the game mechanics of your choice. There are a few goodies to be found on the corpse by characters who survive long enough to take a look - an interesting mix with plenty of potential for further exploits.
Another of these neat little snippets, which pack a tremendous amount into a few pages, not just stuff you can use straight off but also inspiration for further use and development.