A Greek beach has been turned into an arachnophobe’s worst nightmare, as spiders have covered it in a web some 300 metres long....The web has been built by spiders of the Tetragnatha genus. They are often known as stretch spiders, as they have elongated bodies – and in another worrying development for those who fear spiders – Tetragnatha extensa are small enough and light enough to be able to run across water faster than they can move on land.
Quite icky, but a good story seed for anyone in that area.
The webs could be animal vis, or rego vis (so organized and woven!); the bodies of the spiders could be animal vis; hopefully the magi won't over-harvest and ruin the renewability!
Perhaps also, if there is a human victim that the spiders entrap and feast, it produces both corpus and mentem. Are the magi willing to rescue a victim and forego vis? Will this anger the spiders? Conversely, if there are no victims... well, how far will magi go for their precious vis?