Funny that the last post was 'this is one of my older ones' and that post is from 8 years ago :)
So, where, perchance, did the wizard get them in the first place? They make quite a brutal revenge weapon indeed.
A great idea that could spawn a campaign!
Plot idea and history lesson in one. Nice one Manfred.
A neat little critter - the cocoon - spun stone - sounds like it could be used as asbestos, already formed into sheets. This alone could be worth adventuring for.