Terrarium Crypts

[stardustaddict.livejournal.com]

So for my Halloween party I'm putting together some massive goodie-bags for all six of my dinner guests. I'm going to make little dead terrariums with tombstones et al, but I'm wondering how to make the dirt... well, stay would be a good word. Since nothing actually has to grow inside the jars I thought it would be a good idea to make it durable, because I can see one of my friends diving into their bags and their terrariums going all topsy turvy and getting ruined.

I figure glue, but I don't know. Maybe spray some foam with adhesive and cover it in dirt? I've read about, "great stuff", is it? That foam junk. Or maybe MonsterMud in some fashion. I guess I could play around with Elmers and dirt...

Ideas?

Thanx in advance!