Metal Spider Webs

Concept: “Made of tiny filaments of metal, the web can be deployed across any opening.”
Content: A fairly straightforward trap that puts a hurt on anyone who walks straight through it
Writing: Folds the mechanics into the descriptive text
Art/design: Predominant colors capture the core element of this concept: metal and blood
Usability: Easily transplantable into your dungeon of choice (bonus if it already has spiders in it)